I have written a VB.Net (v69586...) application which is targetted for
Windows 2000 SP4 clients running dotNet framework V1.0.03705 and 1.1.

This application works fine on about 50% of the 100 clients and shows an
error dialog on the other machines. The shown error message is rather
cryptic though:
"Application has generated an exception that could not be handled Process id
=0x69c (1692), thread id=0x1e4 (484).

Click OK to terminate the application
Click CANCEL to debug the application" --> Leads to nothing because there is
no debugging environment.

How can I get a clear view on what's going on here?

When you find out what function/sub the error occured in then you can then
put it in a try - catch - end try block

Example:

Try
....

Catch ex As Exception

MessageBox.Show(ex.ToString)

End Try

The message box will show the full error & you will be able to do something
about it from there.

It could be something as simple as a FileIOException because the file is
already open etc. Other problems could be security permissions etc. You
won't know until you do the above

Also, when you build the exe... make sure it is built in DEBUG to maximize
the chances of trapping the error for you to then handle and rebuild it as
the RELEASE version.

I hope the above has given you a few ideas