I think this is your solution, but if not, plenty of ideas down below...
Symptom -- When attempting to print from GroupWise, a box with a yellow exclamation point comes up before the printer dialogue box appears.
Yellow caution symbol with explanation point inside.
Window with yellow exclamation point (!) appears when printing.
Cannot print until after closing GroupWise client and restarting it.
Cause
NDPS was installed on the client but not enabled on the server. The client could not print the way it was configured (using NDPS).
Fix
Disable NDPS on the client
Here's some other possibilities..
Try updating the GroupWise client to 5.5.4 or whatever the latest version is.
Update the printer driver from the Printer manufacturer's website
If Microsoft fax is installed, remove it unless it is needed.Remove any unneeded printers. Maybe too many.
If it is just one person having the problem maybe there's a corrupted file in the C:\WINDOWS\TEMP\GWPRINT or C:\TEMP\GWPRINT directory. Remove all files from the C:\WINDOWS\TEMP\ directory and reboot the workstation
It could be a Windows registry error. Try using GWCA55.EXE to remove the GroupWise client files and registry entries. Reboot and reinstall the client.