I've been trying to get bridge to work but so far no luck. It always redirects to forum index page and doesnt stay "in" gallery. not really sure what should i do :( SMF 2.1 is getting closer to release and i think this should be fixed at some point :)
Please replace the file bridge/smf21.inc.php with the contents of the attached zip file.
Let us know whether it works okay after testing with several users.
PLEASE NOTE: This change has been included in CPG beginning with version 1.6.16