Here's a patch to allow registration to work without register_globals on.  It's pretty hackish, but I did design it to try to prevent SQL injection.  Perhaps someone will have a better idea and some cleanup for this, though--I'm not terribly familiar with the phpGW source.  Most likely, the little function I use to do the replacement on the variables is either somewhere else already, or there's a better way to do it.  Either way, it will NOT break when fed a single-quote (so no SQL injection), however it will die when fed a backslash (though not allow exploitation, to the best of my knowledge).