Hi Crawler,
I believe there are breaking changes from CS 2.0 to CS 2007 to CS 2008. I suggest that you check the guide at docs.communityserver.org to confirm if there is an existing problem with CS 2.0 to CS 2008. I've been following the upgrade patch/versions consistenly so i don't have a handson experience on this type scenario. What i would suggest is that you start by upgrading your CS 2.0 install to CS 2007 before moving to CS 2008. This is safer.
HTH