Default PvP: false is set in the config, but when users join, they can be attacked. Using the /pvp command says PvP is disabled. v2.4.9 running Thermos for MC 1.7.10.

That's way out of date, update pvpmanager.

Do the latest versions work on 1.7.10? I was getting some errors.

They should, i don't test them on 1.7.10 but i try to keep it backwards compatible.
Paste whatever errors you get with latest builds. http://ci.md-5.net/job/PvPManager/