debug build (OSX, cpu render) goes fine.

It takes ages to render in debug builds (after 10 minutes I stopped it, but then opened node editor and saw the composite). For good bug reports, it's always helpful to create the simplest case possible for an issue.
There's always a chance you have a faulty build - for some reason. Trying another build (or from builder.blender.org) would be advised.

Ok, got the the latest "buildbot 51828 MinGW64" from blender.org
Same problems same crashing just like i report above..

also.. compiled a new trunk build.. (51848) and its still broke.. so..
I think it may have had something to do with Commit #51812 or #51819

tried it with the latest 51828 VC build from Buildbot as well..
same crash ..(so its not just MinGW)

You can turn down the render samples to like 10 if you have a slow CPU..(to speed up the render)
the problems is in the Compositor(at the end of rendering)
when it crashes..

did some more work on it..

opened the .blend in another blender version.. muted the blur node.. saved out the .blend file
it works in the new version..

Something is wrong with the new blur node.. conflicting causing the crash..
if i unmute the note and let it try to composite it will crash. so..
whoever made adjustments to the blur node, are were the problems are..

gotta be commit 51819

Campbell:
http://projects.blender.org/scm/viewvc.php?view=rev&root=bf-blender&revision=51819

It seems that going over image pixels, you now go 1 pixel to far, causing bad memory access?

In r51861 there's a fix for node previews, can you check latest svn?

fixed r51867.

works now,
thanks guys. :D