wow
thats crazy
i'd check first (this is just a crazy guess) if your server is up to date w/ mySQL.
second, if it is, then i'd totally uninstall SMF, drop all mysql tables, reinstall smf, and dont apply any mods except for SMF Shop. (there should be no conflicts because no other mods will have messed with the php code)
and then it should go smooth from there. apply your themes and all accordingly
and do what u need to do from there.