Problems updating from mirror

I have a 2.7 server, I've tried to upgrade to 3.0 and I made a mistake so I rollback everything to 2.7 again. But the problem now is that clients are not updating virus signs correctly. Every time I try to upgrade from the mirror it says that the virus signs had been updated, but it's not true it always says the same virus sign and it's and old one. If I try to update with any client from internet it works fine, the problem is only with the mirror. I tried deleting all cache update from mirror and from clients and didn't work. Ports are set ok.
The mirror is a Windows 2003 Server with client 2.7, Lan server, remote administrator 1 and console 1.
Any ideas?