This problem has been going on for a few months now.
Sometimes i get in, sometimes i don't and sometimes in a middle of typing /list or use some other command.. i get the same error also.
I've re-installed mIRC a few times but nothing seems to help.

I've usually found this to happen with certain buggy scripts. If it's not a script, then it may be a firewall/router setting that is messing things up. Other than that, I don't know.

Well.. it wasn't some scripts fault.
I downgraded from latest to 6.17 and seems like it helped..
Thanks, tho!