Yahoo Messenger won't stop opening. How to stop it?

I'm using Yahoo Messenger 10. I have programs that I need to get offline to run. Every couple of minutes or so, Yahoo Messenger comes up saying there was an error (obviously). So is there a way to stop these messages when I'm offline? It keeps interfering with my other programs. Exiting Messenger and reopening it after I'm back online is not an option. I just want it to sit and wait for the connection to return.