Server reboots for some reason?

[Nicolai]

My friend and I have just made a brand new tekkit server and are trying to setup all the plugins and stuff so we can play on it, but once we log on and play for about 30 seconds to a minute it just kicks us and the server shuts down and reboots (as seen in the log)

Does anyone know if it has something to do with the plugins we use: bPermissions and Essentials, or it requires more than 768mb RAM that we've bought from the server hosting company (DaddyCheese)

Bonus info: we've been running a vanilla mc server via DaddyCheese for a couple of months without any problems encountered.