Kernel release shouldn't matter. If you want to implement Bristuff use anabri-asterisk-1.2.17 and anabri-asterisk-zappri-1.2.16. Make sure you rpm -e your 1.4 stuff. Also, there are some incompatibilities in the selintra database going back from 1.4 to 1.2 (specifically to do with ISDN) so you should rpm -e selintra-sail-2.1.15 and physically remove the selintra files from /home/e-smith/db. Finally, just to be on the safe side, remove the extra directory from /lib/modules/uname/. Now you can proceed with your 1.2 installs.
Also, remember that Bristuff will only run with UP kernel (this is a Junghanns issue).
S