The error is from BP BuddyPress. My plugin is just recording the error.
My plugin is calling wp_authenticate to see if the user is a valid user. The plugin does this because it does not wish to block valid users from making a comment.
The wp_authenticate function is is asking if anybody else has a filter for authentication and BP answers that it does and tries to call a BP function that tries to do BP_Signop::get which I assume is looking for a user.
The WP_signup::get is the one throwing the error, not my program.
The SQL at the beginning looks good.
Perhaps someone can answer this over at BuddyPress.
For now update WP and BP so that you have the latest versions of everything.
Keith