uninstall the ac3 codec(if you installed nimo pack then that ac3 is installed with it), mIRC seems to have problems with it, however i find it weird becouse mediaplayer runs mp3 fine when ac3 is installed

https://forums.mirc.com/showflat.php?Cat=...ch=true#Post339

https://forums.mirc.com/showflat.php?Cat=...h=true#Post9098

i first tought it was a bug of the codec, but why is mediaplayer playing it fine then?:)