`make world` exit code

Hackers,

I'm building a new server using 9.1beta2. My build script includes these two line:
   make world -j3 || exit $?   make install-world || exit $?

Much to my annoyance, `make world` seems to succeed, but the script exits with no error message. So the second line
neverexecutes. I commented out the " || exit $?" part and the script worked fine. Is there some random non-success
errorvalue coming from a successful run of `make world` in the beta 2 release? 

I'm on:
 Linux version 2.6.39.1-x86_64-linode19 (root@build.linode.com) (gcc version 4.4.3 (Ubuntu 4.4.3-4ubuntu5) ) #1 SMP Tue
Jun21 10:04:20 EDT 2011 

Thanks,

David