I have a Nextel 7520 BB with v188.8.131.523
I am not on BES.
When I go to delete my old messages or when I am sending messages it will just freeze sometimes. Hard reboot and its back to normal again, until it happens again.
I use Rambler quite often if that makes a difference. I used to have BBToday installed but I uninstalled it.
This only started after I upgraded to 4.1