You are accessing a variable at an address of 8. This usually means that you have a nil
object reference and you are trying to access the member at offset 8. The address 00498AD7
is the location in the executable of the code that caused the fault. If you have a detailed map file for your executable you could cross-reference that address to a function in your program. However, that is usually of limited use.
It's easy enough to debug this. Make sure that the debugger options are configured to break in the IDE when an exception is raised. Then run under the debugger and when the error occurs the debugger will highlight the line of code which caused the error. Or perhaps you have to look up the call stack a couple of levels.
Beyond the immediate problem, using a tool like madExcept or EurekaLog will allow you to debug such problems when they occur remote to you. For instance on your customers' machines.