error notification on anonymous access attempt
I have a website using Tikiwiki 5.1 that is being hit by spammers/hackers (www.omahacopwatch.com). I've removed the gallery that they were trying to access so now all they get is an error message. However, each time an anonymous party tries to access the missing file, the error message still runs about 14K. I would like to change the error message to some simple text message which would drain less of my bandwidth.
Any suggestions on how to change the error message in Tikiwiki are appreciated.