I am currently having a small problem with essentials, in that it no longer correctly registers AFK players. with it set to 300 (as I did before I moved to a hosted solution) it now sets players afk as soon as they log in and it no longer freezes them in place. Players then become invincible and do not gain any logged playtime.
UPDATE:
In-case anyone else has this problem, it's caused becuase Essentials 2.9.3 is written for Minecraft 1.3 but Tekkit 3.1.2 is only Minecraft 1.2.5