Switching off startup errors

Every time I start my linux machine I get the Mozilla splash screen
starting up with the following error:

"Unable to run the command specified. The file or directory
file:/cdrom/index.html. does not exist."

I have no idea where this command has come from nor how to switch it off.
I would really apreciate some help here.
Many thanks
Bob :cry:

I am guessing you are using knoppix what can i say when you install knoppix to a harddrive you get errors on bootup might wanna check the knoppix bugzilla for that