common problem with Diamond Tweak/Advance Config...as stated by fantecho, there are numerous thread
This is straight from the "Essentials:
"Issues with answering your phone when a data connection is open (answer buttons don't do anything)? Looks like a tweak messes up a registry key that affects this. [HKEY_LOCAL_MACHINE\Comm\ConnMgr\Planner\Settings], make sure SuspendResume is set to #777 (not anything containing GPRS). This issue seems to be related to Advanced Config. source Added 1/7/09:"
Here is one of the threads about the issue
http://forum.ppcgeeks.com/showthread.php?t=65350