Q: Shake crashes when compositing at 6K?

Does anyone have a set of cache / diskCache settings that tune up shake 4.1 to work with 6K images?  I'm currently crashing about every 20 seconds or so with the following errror:

shake(1511,0xa0338540) malloc: *** mmap(size=104861696) failed (error code=12)

*** error: can't allocate region

*** set a breakpoint in malloc_error_break to debug

error: memory allocation failed

I have a new 12core 48G RAM OSX 10.6 machine.

I made an attempt to create a custom memory.h file  (see below):

diskCache.cacheMemory = 512;

diskCache.cacheMemoryLimit = 1024;

diskCache.cacheSize = 51200;

diskCache.cacheMaxFileSize = 16*8192*4320;  //8K 16bit Holds 8K 10bit image

diskCache.cacheLocation = "/scratch/shake";

cache.cacheMemory = 256;

cache.cacheMemoryLimit = 512;

Shake still crashes. W/O the memory.h file.

Any help would be appricated...

thx