Does the bot have +o when you enter the channel (@ next ot it's nickname)?
If no, it could be one of three, things, other wise one of two.
If no, then you may have changed the neep-op setting for the channel to send this message. Eithe change these setting using ".chatset #channel nee-op" or use the cleanneeds provided by slennox on the egghelp.org site.
Otherwise, it could be a script designed to do this.
ANother possibility is it's your info line. You may have saves a info line in your bot user-record, which is displayed on the channel. Either remove the ifno line, or set the channel -greet with .chanset.