Let's try from the very beginning.
1) try several versions - for example Platinum and SoD
2) if it's a Hamachi issue - try pLan for instance
3) as Vic suggested - uninstall DirectX X and install a new one - I don't know if it will help, but it's worth a shot.
4) if the internet is via a router or gateway - try connecting by bypassing them - 5 minutes is enough to check this option.
5) disable the firewall and antivirus; if there is a same-name firewall - turn that off too.