ok that fixed the errors:

[15:11:38] Read-only list:
[15:11:42] Syntax: /readonly add #channel
[15:11:42] Syntax: /readonly del #channel
[15:11:42] Syntax: /readonly list
[15:11:51] Added #fudge to read-only list

However it did make the channel a read-only channel ... I was still able to send text to the channel.

Code:
 

on ^*:INPUT:$(%readonly):{
  if ((/* iswm $1) && ($ctrlenter)) return
  echo 4 -at This channel is read only.
  haltdef
}

alias readonly {
  if (($1 == add) && (#* iswm $2) && (!$istok(%readonly,$2,44))) {
    set %readonly $addtok(%readonly,$2,44)
    echo 5 -at Added $2 to read-only list
  }
  elseif (($1 == del) && (#* iswm $2) && ($istok(%readonly,$2,44))) {
    set %readonly $remtok(%readonly,$2,1,44)
    echo 5 -at Removed $2 from the read-only list
  }
  elseif ($1 == list) {
    echo 5 -at Read-only list: $replace(%readonly,$chr(44),$chr(44) $+ $chr(32))
  }
  else {
    echo 5 -at Syntax: /readonly add #channel
    echo 5 -at Syntax: /readonly del #channel
    echo 5 -at Syntax: /readonly list
  }
}