Remote Desktop connection problem

Never had a problem with client terminal services sessions for two years but
have had the following problem a number of times and wan to try and identify
the source before it spreads.

When trying to open a client terminal services session get the floowing
message on the client.
'The Terminal server has ended the connection.'
If the user is a local admin then the connection is OK.

On the server I get an event 1004 with the error.
"The description for Event ID ( 1004 ) in Source ( TermService ) cannot be
found. The local computer may not have the necessary registry information or
message DLL files to display messages from a remote computer. The following
information is part of the event: The event log file is corrupt.."

Any help appreciated.

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