i just opened a rc5 test room and couldnt get in either... disabled the FancyEntry=1 and had no problems.I think this was a problem for shareguard or another client a few weeks back and it was fixed for for version rc5.( i remember readin sumthin about it anyways) So i'm sure the next version rc6 or whatever it will be should have the problem solved FancyEntry=0 <---- disabled
so for the time being u could always use RoboMX or WPCC which is a pretty cool chat client.... WPCC looks almost identical to your WinMX .It needs winmxworld caches placed into it or use the new 3rd party patch you can download it
here if you don't already have it.