I tried to recharge the AC on my 97 c230 and the Gage went into the red. What does this mean

It sounds like high pressure caused by a system restriction at the very least. Air conditioning repairs are really not for the "home mechanic". You are ill equipped to diagnose and repair systems when a problem is present. It's also quite environmentally irresponsible to recharge a leaking system, if the system has merely leaked out refrigerant from a leaking component. Diagnostic testing is needed to detect and repair sources of leaks, verify system integrity with no debris from failed components, and then once all is well, the system can be charged.