VB Editor complains of undefined variable for VBE

I have a project that uses an add in to deliver most of the functionality.
This included a proprietary save in which I store data on the *** for the
next time.
A request was made to be able to "minimise" the form to look at the ***. I
put this in but this then exposed a method by which the user can save using
excels save not using the forms methods that store vital data before the user
exits.

To catch this I need to put a workbook_beforesave() event in to the
work*** itself to call a function in the addin to do the stores as if the
user had used the form save.


I have used code from http://www.cpearson.com/excel/vbe.htm but when I
compile/run I get variable not defined errors on the "vbext_pk_Proc"

Function ProcedureExists(ProcedureName As String, ModuleName As String) As
Boolean
On Error Resume Next
If ModuleExists(ModuleName) = True Then
ProcedureExists = ThisWorkbook.VBProject.VBComponents(ModuleName) _
.CodeModule.ProcStartLine(ProcedureName, vbext_pk_Proc) <> 0
End If
End Function

I tried Dim vbext_pk_Proc as ProcKind, but then I just got a user defined
type error

Looking in my object browser I don't seem to have the vbext_<> set of
declarations but I can't figure how to reference it.

Help!!!
.