an ODB to 2+2 adaptor? Yeah I've used one. Seems to work ok with my old ODB-rs232 cable. Can't even remember where I got my ODB-rs232 cable from now but it seems to work better with older stuff than USB cables. Just means I have to keep an ancient laptop which still has an old fashioned serial port on it for this purpose!
I find vwtool.exe works better with g40 digipants than vagcom. There's a download link I put in the FAQ section somewhere.