xmem problem

Hi,
I’m using DC version 9.52 and I’ve a problem with this code:

a=xavail(NULL);
b=xalloc(MemSize);

The problem is that a=70130 and MemSize=62015 but the compiler give me a run time error like this:
xmem allocation failed (out of memory)

Why?

What processor or core module are you using?..