I have an HP tx2510 laptop and have been suffering from the BLService.exe runtime error for a long time. It usually happened when I plugged in either my HP all in one printer or my Blackberry to one of the USB ports. Both of these devices have memory card slots and show up as an external drive on my computer.
I applied an HP softpaq update (sp40669) which appears to have fixed the error indicating that BLService.exe has stopped working when I plug in my printer or Blackberry.
The patch description says the problem occurs when an external USB drive is connected to the notebook, and the fix modifies the Microsoft BitLocker Program (BLService.exe) so it only monitors the internal hard drive.
The link to the HP site where I found the fix is:
HP Update for Microsoft BitLocker Program*
The link to the HP download for the patch is:
HP Update for Microsoft BitLocker Program*
Hope this helps all the HP notebook users with Vista that are having the same problem.