[ic] Auto-create of user failed pt 2

[Cameron]

I'm still having major issues with auto-creation of users from
log_transaction. Here's my error message.

203.59.203.83 TCqScGsN:203.14.169.19 - [08/February/2003:03:38:52 -0500]
store /cgi-bin/store/process Safe: Auto-create of user failed. at (eval
1395) line 1.
>
>  die errmsg("Auto-create of user failed.");
>

I've tried narrowing this down by putting just this tag on a page (with the
appropriate tables entry):

                [userdb
                        function=new_account
                                assign_username=1
                                        password='123'
                                                verify='123'
                ]

It's not creating the user, and it's not reporting back any error messages
in the error log. I've even had the site upgraded from 4.8.3 to 4.8.6.
Nothing seems to help :( Does anyone have *ANY* ideas? I've tried migrating
the site to sql, i've tried removing all possible conflicting users from
userdb, and i've just about exhausted my limited knowledge of interchange. i
really need this to work, cause i can't change the order status in the
backend without it.