Thanks for your prompt response.
Ignore is disabled, and downloads aren't blocked.
I get this sometimes at home, so than it's the sender.

When I tried at the university, I got the same msg. I can connect to a network and channel, but a DCC gives the same.
They must be blocking some ports, is it possible to set mIRC to different port for DCC? Is there a way to see which ports they are blocking?