Recheck your cable routing, make sure it is correct. Especially under the bottom bracket. Is the loop on the rear derailure large enough? I t sounds like you have some extra friction on the cable some where.
Edit: I didnt see any mention of you installing a 10 speed chain. You need to run the narrower 10 speed specific chain with the 10 speed cassette.
Last edited by ls01; 08-05-10 at 11:37 PM.
Reason: 'cuz sometimes the hampster falls off the wheel