The only Neogeo games which can run out of memory are actually the PCB sets (svc, kof2003, mslug5) and few others, all in a video mode higher than 480P. They're already fix (i will give the code to +T+). the "OUT OF MEMORY" error means that a call of malloc() failed, so definitly not an rom issue. If it is not a radioactivity issue, or if you don't use a special revision of the Xbox with 16 MB of RAM, i suggest you to perform a clean install. If it still does not work i can give you the number phone of an exorcist.