The whole 'burned CDs can damage your laser and CDs' is perhaps a rumour that can be traced back to the late 80s when the trend first started. Some (the conspiracy theory minded) think it was started by the big music companies to discourage illegal copying.
I've never heard a good (physics based) explanation how a read laser could damage a CD/DVD. Constantly reading a bad copy (as another posting suggested) is the only thing I could see having any ill effect.
I have a homemade update DVD in my car and I'll let you know when the Blue Meanie burns up
