Im trying to render into a 2048*2048 texture using bmap_process.

I do this:
bmap_zbuffer=bmap_createblack(2048,2048,32 );

then this:
bmap_process (dest, src, mtl_compute);

both dest and src are supposed to be 2048 in size..

always seems to default to some weird size no matter what I do, and bmap save wont work and so on...
can someone explain maybe how this is supposed to work?

bmap_zbuffer is a function, you should call

bmap_zbuffer(bmap_createblack(2048,2048,32));

Oh! thanks, that's fixed it...