I don't really know what's the use of this one, since my Marketplace is just working fine on my computer.
Apparently some people, those outside in the USA are still having problems connecting to the Zune Marketplace since the software disables the option if you're location is set to a different country other than the USA
A hack posted by Fez, a member of DarkZune forums, fixes this problem. The program is called zInternational (z for zune and i for iPod, can't make that too obvious..just like zPH) fixes this problem. It unblocks marketplace option and let's you update your play count in zune social.
My solution is simple. When registering your account, set your country to USA. that should work fine.