Hey Guys,
I followed the advice of musclenerd on twitter who advised to use redsn0w for those having trouble installing cydia after the GP jailbreak. I too could not get the loader program to install cydia. So, I used redsn0w after GP and only had "install cydia" selected in the options and it installed cydia and everything appears to be working fine. I had to chase down redsn0w but I used the most recent version I could find (0.9.7, I believe as I am at work right now) which is not on the main dev-team page. I saw many credible folks on twitter saying this method is fine and so far so good.
when you did it this way, you only installed Cydia? Did you have to follow all the directions of redsn0w? Doesn't it restore your device and all that?