Hi Mary,
Yes please, because of the lines:
line 1379 of /mod/forum/lib.php: call to forum_is_user_group_discussion()
line 1474 of /mod/forum/lib.php: call to forum_filter_user_groups_discussions()
line 43 of /blocks/course_overview/locallib.php: call to forum_print_overview()
in the stack trace, so I'm 90% sure.
Cheers,
Gareth