Re: Register vs wp-signup : passwords vs signup question
Is the plugin you’re referring to this one?
If so, it states that it is not updated to the newest version of WPMU and that there are no plans on updating it. Also, again if this is the plugin with which you are having issues, then you will more than likely not get much support on the BP.org forums. Since this is a premium plugin, the developers of it should be doing the support. In other words, you are not going to have someone solve the issue here for free when someone else is making all the money.
If it is a free, GPL plugin you’re having issues with, please provide the link here. Also, contact the developer and make sure that it is compatible for use with BuddyPress in general and that it has been update to the BP 1.1.x series.