Well some common problems with soldering in mod chips is that the soldering points are so darn small... its very easy to bridge them and it also very hard to get nice good connections. That is of course unless your a seasoned pro at soldering to very fine points. I myself just paid the extra 25 bucks and got a DMS4 EZI PRO... Ive got a fully modded fully functional self installed mod chip now and it was worth the extra money. Even if you break it down the chips are at least 50 each and installs at cheapest are around 40 dollars each... so thats 90 instead of the 75$ I paid and I did it myself.
TO answer your question Id say post some pics of the install if you can and let the fourm memebers see what they make of it.