Problems with IAR and programming

I have a target board with a MSP430FR5729. I am using IAR EW6.5 and a
MSP430-FETUIF. I have a MSP-TS430PW28 connected to the FET module and 4
wires going to my target board (Vcc, ground, Test, RST). I have used this
sort of setup many times. My target board has a 12V input and it generates
11volts to be used on board to generate 3.3V and a few other DC voltages.
When I connect the cable from the PW28 board I can program the board and run
it. If I connect the 12 volts to my target board the IAR crashes and I have
to turn my PC off and on. When the 12V is not on the Vcc is 3.32V and if I
have the 12V connected and no FET the Vcc is 3.29V. I cannot see any shorts
to ground and the whole target board draws 17mA when no high power devices
are connected (3G modem). I can program in a led flash and this will work
with no 12V connected. If I remove the FET and apply power the fled will
flash. It seems the program runs but it will not download the program when I
have the 12V connected. I checked the notes from TI and can see no hints as
to what is happening. 

 

 

Any suggestions?

 

TIA

 

Peter