This is not how you pass strings around with natives. You have to use get_string and set_string
http://amxmodx.org/api/amxmodx/get_string
http://amxmodx.org/api/amxmodx/set_string
In your case get_string should be what you want. Also
MaxClasses is not needed, you can get the current number of classes by using ArraySize(ZombieName).
PHP Code:
ArrayGetString(ZombieName, ZombieNameReal[id], Name, sizeof(Name))
This is also wrong, you should use charsmax for strings, not sizeof. Otherwise, you risk not having space for the null terminator.