I suspect that probably there is a damaged or faulty data - which might be come from a dwg or ifc - in the user's local data who got this error (I guess during a Send&Receive).
Probably the fastest solution is to re-share the project:
1. Save the teamwork project as a PLN
2. Close the teamwork project
3. Open the PLN file, but use the File menu > Open dialog (so not the dialog which appears when ARCHICAD starts)
4. Select the file in the Open dialog, a checkbox should appear at the bottom of the dialog: "Open & Repair select file", check it
5. Open the PLN file
6. Re-share the PLN file