Ah, I think I solved it. The Superadmin > Sites seems to allow themes on a site by site basis. Is this correct?
Tady,
As fastpipe recommends you shouldn’t be moving the mysql directory like that. Use a symbolic link – this is how binary installs are usually done. You probably installed the MySQL binary, and when you updated to Snow Leopard Apple removed the symbolic link to prevent it from starting up – as there maybe problems with the 32-bit version on SN.