Recently I had an Issue with BAM Bm.exe. I tried to run it through command prompt got a wierd error sayign its not a Valid Win32 Application. I thought its an issue since I installed BizTalk in 32 bit mode on a 64 Bit Windows 7 machine. On googling found nothing ..seems nobody encountered it ever. Finally I thought google wont help looked at bm.exe and found the file size was 0.
Seems it got corrupted somehow. By replacing it with a new bm.exe solved the problem.
So basics do help when google fails to help you.