Using J1.5RC and CB1.1, I have the same problem that user cannot update his profile through front-end even after applied this fix for Warning: Invalid argument supplied for foreach() in /home/mparisi0/public_html/components/com_comprofiler/plugin/user/plug_cbcore/cb.core.php on line 240.
Meanwhile Update through back-end (CB1.1 under joomla administrator) works fine.
I have noticed that the page does not call task saveUserEdit in the comprofiler.php, and it you try to post it through the browser an error arise as “session expired and/or not enabled in your browser” meanwhile it is enabled, the error arise in case of using firefox or IE7. This issue almost related to these many opened issues for “session expired…..