Hi Hermann,

>However, from time to time I get the "Session Number Is Invalid" error, from a cusdatasessionid.restoresessionid method.
>Is there some sort of standard problem that causes this kind of thing?

Yes, setting datasession to a number that doesn't exist. If you haven't already, I suggest using the Debugger to track down the line - I imagine it looks like: SET DATASESSION TO (m.vSession) - and see what you can find from there.