What I feel its due to a bad target or bad emulator.. As you've already tested on different boards, emulator seems to be an issue. (I hope you've selected XDS100v2 and not v1 or v3 in Target configuration)
Also, check these links out:
http://e2e.ti.com/support/microcontrollers/tiva_arm/f/908/t/195847.aspx
http://e2e.ti.com/support/microcontrollers/tiva_arm/f/908/p/310997/1083173.aspx
Regards,
Gautam