Lets try this code. Put it into new remote file. ( Alt+R, File, New.. )

Code:
on $*:text:/^!commandadd !?(\S+)/iS:#:{
  if ($nick !isop #) { echo -ag You are not OP }
  else {
    writeini commands.ini commands $regml(1) $$3-
    echo -ag $readini(commands.ini,command,$regml(1))
  }
}