Hi There
I'm not sure why yum is trying to upgrade dahdi. The sail rpms don't specify a release level dependency, just a general one. SAIL doesn't really care what asterisk or dahdi you are running, as long as they are present.
In any event, you should be able to run your upgrade without the Digium and Asterisk repos (the base repo is enabled anyway I think)
yum localinstall smesailenv-4.0.0-11.noarch.rpm sail-4.0.0-58.noarch.rpm
Make sure that, as a minimum you back up your sail database (/opt/sark/db/sark.db) before you run the upgrade. If it all goes wrong then you can recover by removing sail; then re-install the latest 3.1.1 release, copy your saved database back and then run
sh /opt/sark/scripts/updatedb.sh
That should get you back to 3.1.1.
Kind Regards
S