Humpy -
You have to specify which bots are supposed to attack. That is the error message saying it doesn't know to whom the command applies. The full list of options is in section 2 here:
http://wiki.eqemulator.org/p?Bot_Commands
But basically, you have to target the Mob to attack and then enter the command "^attack ownergroup" to have all boys in your current group attack that mob. That said, as discussed above, it still isn't working.