I am having a similar problem using the "latest beta" V3 download this AM from the website. Default identity not being created at initial logon.
I get an error 500 on first logon attempt.
This shows up in the logs:
[29-Jun-2009 12:03:45] PHP Warning: ob_start() [
ref.outcontrol]: output
handler 'ob_gzhandler' cannot be used after 'URL-Rewriter' in /opt/roundcube3/index.php on line 48
[29-Jun-2009 12:03:48] PHP Fatal error: Call to a member function exec_hook() on a non-object in /op
t/roundcube3/program/include/rcube_user.php on line 403
Future log on attempts work with the same account work, their is no identity since the default identity is NOT created at first log on.
Tested with 3 different accounts.
V2 stable had no problems when I did this last week.
Hope that helps!