Re: The MSComm Error 8021 with desc.: "Application-defined or object-defined error"

From: Rino Ouellet (rinouellotravail_at_globetrotter.net)
Date: 08/24/04

  • Next message: Max Krayz: "Use SNMP in VB 6" 
    Date: Tue, 24 Aug 2004 23:05:29 GMT

    Thanks for your answer Mr Birch.

    But I forgot to tell you the following details:

    -The word client, here, means a person which is a client of our company.
    -I use : Windows 2000 Professionnal Service Pack 4 (to develop the
    application using Visual Basic 6.0 Professional Edition)
    -Our client use : Windows XP (to run the .exe I made with Visual Basic)
    -Note: I think the MSComm control causes the error.

    So I would like to know possible causes of this error. I would (also) like
    to know what could cause an error retrieveing the Device Control Block when
    using MSComm control, even if you think it's not related to the current
    problem (because this error happens sometimes on the computers of our
    clients).

    Thank you 

    -- 
Rino Ouellet
Multi-Électronique
Courriel/E-mail: rinouellotravail@globetrotter.net
"Randy Birch" <rgb_removethis@mvps.org> wrote in message
news:eQmDARiiEHA.3288@TK2MSFTNGP10.phx.gbl...
> Since you appear not to be positive that the comm control is causing the
> error, here's another wild-ass guess that may explain why your user
> experinces a failure but you don't.
>
>       Multihomed Master Browser May Cause Event ID 8021 and 8032
>
> Q135404
>
>
> --------------------------------------------------------------------------
------
>
> The information in this article applies to:
>
>   a.. Microsoft Windows NT Workstation versions 3.5, 3.51, 4.0
>   b.. Microsoft Windows NT Server versions 3.5, 3.51, 4.0
>   c.. Microsoft Windows 2000 Advanced Server
>   d.. Microsoft Windows 2000 Server
>   e.. Microsoft Windows 2000 Professional
>
> --------------------------------------------------------------------------
------
>
> SYMPTOMS
> Your computer running Microsoft Windows NT or Windows 2000 may
occasionally
> log one or more of the following events in the Event Viewer System log:
>   Event id: 8021
>   Source: Browser
>   Description: The browser was unable to retrieve a list of servers from
the
> browser master <PDC> on the network \device\<protocol_netcard>. The data
is
> the error code.
>   -or-
>   Event id: 8032
>   Source: Browser
>   Description: The browser service has failed to retrieve the backup list
> too many times on transport of <protocol_netcard>. The backup browser is
> stopping.
> This symptom occurs if:
>
>
>   a.. Your computer is a multihomed computer (that is, it may link
> simultaneously to two or more subnets using multiple network cards).
>
>
>   b.. Your computer is a master browser.
>
>
>   c.. Your computer is running the TCP/IP protocol.
>
>
>
>
> CAUSE
> The following situations can cause this symptom:
>
>   a.. Your computer network cards are linked to the same subnet.
>
>
>   b.. Your computer network cards are not linked directly to the same
> subnet, but are linked indirectly through other subnets that they are
> connected to.
>
>
>   c.. The master browser is using an incorrect subnet mask.
>
>
>
>
>
> WORKAROUND
> To work around this problem, do one of the following:
>
>   a.. Unbind all but one of the TCP/IP subnet transport bindings from the
> workstation service.
>
>   -or-
>
>
>   b.. Remove all but one of the network cards or RAS connections.
>
>   -or-
>
>
>   c.. At the command prompt type the following command:
>     net stop browser
>   NOTE: This option prevents you from receiving computer browse lists from
> other networks.
>
>
> After you perform these steps, wait at least 10 minutes to see if the
errors
> still occur. If they do, continue troubleshooting by cross- referencing 2
> pieces of information. First, check the transport that failed in the event
> log. For example, error 8021 displays a message similar to the following:
>   The browser was unable to retrieve a list of servers from the browser
> master \\<server_name> on the network \Device\NetBT_<driver_name>. The
data
> is the error code.
> The important data is NetBT_<driver_name>, which indicates the protocol
and
> netcard binding, also known as an "endpoint." The potential protocols you
> may see are:
>   Nbf_netcard = NetBEUI NetBT_netcard = TCP/IP (or NetBIOS over TCP/IP)
> NwlnkIpx = IPX/SPX (NwLink) [will not indicate netcard] NwlnkNB = NetBIOS
> over NwLink [will not indicate netcard]
> After you have determined the failed protocol endpoint, check the working
> status of the Browser service on all installed protocols with the Windows
NT
> resource kit program Browstat.exe. At a command prompt, type the following
> command:
>   browstat status
> This will enumerate the browser status on all endpoints. Look for the
> message Browser is NOT active on domain under each endpoint. Disregard
data
> about endpoints that list "NdisWanX" (such as Device\NetBT_NdisWan5);
these
> are RAS endpoints and will usually list the error anyway.
>
> You should find a protocol match between these two steps. The next step is
> to record any important information about the protocol from Protocol Setup
> in the Network tool in Control Panel. Then, remove the protocol, restart
the
> computer, and see if the error no longer gets logged (remember to wait at
> least 10 minutes). Then, try reinstalling the protocol, checking for the
> error, and reapplying the service pack that exists on the current Windows
NT
> installation.
>
> If the error persists after a protocol reinstallation, you may have
problems
> with the network adapter card. Check with the vendor to see if there is an
> updated driver, or try another network adapter card.
>
>
>
> STATUS
> Microsoft has confirmed this to be a problem in the Microsoft products
that
> are listed at the beginning of this article. We are researching this
problem
> and will post new information here in the Microsoft Knowledge Base as it
> becomes available.
>
> Additional query words: tcpip multi-homed multi homed
>
> Keywords : kbnetwork
> Issue type : kbbug
> Technology : kbWinNTsearch kbWinNTWsearch kbWinNTW400 kbWinNTW400search
> kbWinNT351xsearch kbWinNT350xsearch kbWinNT400xsearch kbWinNTW350
> kbWinNTW350xsearch kbWinNTW351xsearch kbWinNTW351 kbwin2000AdvServ
> kbwin2000AdvServSearch kbwin2000Serv kbWinNTSsearch kbWinNTS400xsearch
> kbWinNTS400 kbWinNTS351 kbWinNTS350 kbwin2000ServSearch kbwin2000Search
> kbwin2000ProSearch kbwin2000Pro kbWinNTS351xsearch kbWinNTS350xsearch
> kbWinAdvServSearch
>
>
>       Last Reviewed: February 12, 2001
>       © 2001 Microsoft Corporation. All rights reserved. Terms of Use.
>
>
>
>
> --------------------------------------------------------------------------
------
>
> Send feedback to MSDN.Look here for MSDN Online resources.
>
> -- 
>
> Randy Birch
> MVP Visual Basic
> http://vbnet.mvps.org/
> Please respond only to the newsgroups so all can benefit.
>
>
> "Rino Ouellet" <rinouellotravail@globetrotter.net> wrote in message
> news:wNNWc.51986$X12.24140@edtnps84...
> : Hello.
> :
> : Can someone tell me the possible causes of the error I have?
> :
> : I have the error 8021 (Application-defined or object-defined error) in a
> Sub
> : that contains the line
> :
> :    FrmMain.MSComm1.Output = (Q$)
> :
> : where Q$ is a string we send on Com1. It contains some other lines, but
it
> : only assign a variable to the value 5 and set an Image visible and
another
> : image invisible.
> :
> : In the current circumstance, I suppose the error 8021 is caused by
MSComm
> : control. The description of the error 8021 for MSComm control is
"Internal
> : error retrieving device control block for the port".
> :
> : So what could be the causes of this "Internal error retrieving device
> : control block for the port"?
> :
> : Note: The error happens on our client's computer but we can't reproduce
> the
> : trouble on our computer and it seems to work properly here. I use Visual
> : Basic 6.0.
> :
> : Thank you!
> :
> : -- 
> :
> : My E-mail: rinouellotravail@globetrotter.net
> :
> :
>
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