Gallery2 not available

I'm using D6.6 + G2.3 now and I found if the user sync is fail for one account and when I use this account to login to Drupal, I'll get a error screen and it let me download a error report from http://example.com/admin/settings/gallery/report/download.

I found the error message in the above report is "Gallery2 not available". And I finally delete that acocunt on G2 and try to sync again, when the sync is ok, I can use that account in Drupal now.

I'm not is it a bug or whatever, just for your reference.