Yes the 1/5 and the fact that you may have a bad map (not that BD's map is bad, but bad for your application) could all be causing tyou to have a twichy throttle.
You can use a "0" map from powercommander, should be on the disc that came with your PCIII. Upload it and see how the bike feels with just the "0" map in it, if it still the same then go over your install and make sure all connection are right. Did you install a TRE with this?
I went into the map thread and got the version 3 and 4 of chris's map and also Ground Zeros map, so far GZ map seems ok, but I ahve yet to get on it. I got the Ivan map with my PCIII as I bought it from him, but it seems really rich for my location. I plan on hitting a dyno this weekend and seeing what the stock Ivan map, GZ map, and chris maps do on my local dyno.
In the end I know I may need a custom as well.