so last night i was doing some shots for a wedding rehearsal and all the sudden on my canon 40D i got a message on the display the said err 99. fortionatly i had my 20D with me as my backup body so i just grabbed it and started shooting. on my 40D i was using a canon 60mm f/2.8 macro and a 580 ex but all the contacts were clean. after about 20 mins passed i grabbed the 40D and it was working fine after removing and putting the batteries back in. anyone have any ideas as to what err99 means? i have to shoot a wedding today at 3 so hopefully i will get some replies before then.