The profile error is discussed earlier in this topic. There should be a solution a couple of pages back. "Could not get instant message post information" means, in this case, that they waited to reply until after the main window had refreshed - when the main window refreshed, the message was deleted from the database. The script is trying to get the username/user id of the person the user is replying to, but can't because the message has been deleted.
You can't find it because it isn't there yet.
Check the im_prefs database table and make sure there's a column called admin_allow_ims and that none of the values in that column are zero.