Locked workstation breaks code?
 

I have seen similar questions posted elsewhere, but nobody has ever got an
answer!

I wrote a small app (VB.NET) that copies some data into excel and pivots it.
It works fine.

But if your workstation is locked while the application is running, Excel
give this error dialog - "Not enough system resources to display
completely". Then my application stops. Surely I should do some better
error handling, but what causes Excel to give this error?

Again, the application works fine as long as the workstation is open - I can
even work on lots of other tasks while it runs, no resource problems at all.
But when the workstation is locked, this error message pops up.

I am using VB.NET 2003, Excel XP SP3, Windows XP Workstation SP1.

Scott