Workgroup Manager

[mpes]

I created a workgroup for our students with an associated group folder of the same name. The group folder worked well originally showed up in the dock normally. Now, at the beginning of a new school day, a question mark has replaced the folder and the students no longer have access to that group folder. No settings in WGM were changed. Has this occurred to others, if so why, and can it be corrected without re-creating a new folder?
Thank you for any enlightenment.
mpes