whoops, forgot md5 takes more paramaters

$md5(text|&binvar|filename,[N])
Returns md5 hash value for the specified data, where N = 0 for plain text (default), 1 for &binvar, 2 for filename.


//echo -a $md5(C:\mirc\mirc.exe,2)
b766003f431cad186bd115f5761592d1

That ,2 is very important :P