Hi,
It's hard to tell what is happening there, looks like you may be trying to read froma NULL pointer and the debugger returns this error. Do you have more specifics on what line of the code is causing the error?
Also it may be a good idea to monitor the value of the varibles to see if there is any array that could be loosing it's memory space.
Please post more specifics so that we can work on this.
Regards,
Juan Carlos.
N.I.