Hi Stephan, you have to find out, which exception is this, by looking into xPSR core register. It might be hard fault.
Once you know the exception number, you can hook your exception handler into the vector table. You will find vector table in the vector.c source file in the BSP library. By default, isr is configured to DEFAULT_VECTOR, which is the _int_kernel_isr() function of the MQX dispatcher. So I usually put my own function, like void HardFault_Handler(void), to vector table offset 0x0c.
Inside my_kernel_isr(), you would typically want to see the interrupt stack frame, CPU register content at the time of exception. As you are in CodeWarrior GCC, you can look on the link below:
http://www.freertos.org/Debugging-Hard-Faults-On-Cortex-M-Microcontrollers.html
and use directly the HardFault_Handler - just remove the static keyword, as you need the HardFault_Handler to be global, as it is referenced from vectors.c and it will be implemented in your application, main.c, for example.
Now, put breakpoint to this HardFault_Handler() and see the registers read by prvGetRegistersFromStack(). Typically at most interest would by "lr" and "pc". For example, "lr" would have an address of an instruction that a return from a function call would return to.
By looking into the .map file or using you debugger, you now know, which function has been executed by the CPU when exception occured.
By this you only find, which function causes the problem. Next, you will have to think why this occurs, and give more application specific debugging effort to find the root cause.