Hello Chris.
I did what you told me, but it didn't work. However, I was exploring other registry entries and set the value “0” to the item Logging under the key Computer\HKEY_CURRENT_USER\SOFTWARE\Sybase\PowerBuilder\22.0\Workspace\<MyWorkSpace>.pbw\SourceControl (where “<MyWorkSpace>” is the name of the conflicting workspace) and this fixed the problem.
This means that the error occurs when the Log All Activity checkbox is checked in the Source Control tab of the Properties of WorkSpace dialog box. I'll post a ticket for this inconsistency to be reviewed.
Thanks again!