First, my contacts are clean, but theres a problem with communication. In ETTL mode on flash the zoom isnt working regularly, and often in low light (aperture priority mode on cam) the camera seems to meter for available light instead of acknowledging flash will fire. I end up with either underexposure or trails from cam shake. Also, last 2 shots I took the camera showed "error 99" and shut down.
I have a wedding to shoot on Sat.

