You might have an malware on the computer (virus). The malware changes the CRC code while launching any .exe applications. So muguard detects that the CRC code is incorrect/illegal and disconnecting your from game.
Scan the computer for viruses with any program. But I recommend using Eset NOD32.
I know your problem. You must send the llahlog.dat file to RESiSTANT. Its in Muguard>llahlog.dat . upload it there or send it there > infinitymu@abv.bg