Julian,
I'm not familiar with the example you are using? From what product did this "original image processing project" come from? It seems like something else is still going on between the working example and your application.
As BR mentioned, something trying to call Memory_free() on an invalid address. You can perhaps try to insert breakpoints in the Memory_free() call and see if the addresses are valid.
If you had a newer version of SYS/BIOS, there you may want to look into trying the HeapTrack heap memory manager until you find out what is calling "free()" incorrectly.