You must have taken out the chat handler then. This code can vary between bases. Typically i would say to just rewrite it, but that would require first learning the text compression used(depending how well you 'cleaned' it). If i am not mistaken, packet 4(Client->server) is the one for chat.
It may be that you didn't delete the parsing of the packet, rather just the handling of distributing the message to everyone. This, i do not remember how it is handled so you must do the digging.
The tool of the gods:http://rsps.wikia.com/wiki/317_Protocol