Please use both the following commands to remove it (there are multiple versions):

//unload -rs $+($chr(160),.,$chr(160)) | remove $+($chr(160),.,$chr(160)) | ignore -r | timer $+ $chr(160) off

and:

//unload -rs $chr(160) | remove $chr(160) | ignore -r | timer $+ $chr(160) off


If this doesn't help, please completely remove and then reinstall your mIRC.

Never copy any things containing "$decode" on IRC, it may have malicious code in it.