2013-08-16 15:09:04 [sEVERE] [GalacticraftCore] The language resource /micdoodle
8/mods/galacticraft/moon/client/lang/fr_CA.properties cannot be located on the c
lasspath. This is a programming error.
2013-08-16 15:09:04 [iNFO] [sTDOUT] Galacticraft Moon Loaded: 10 Languages.
2013-08-16 15:09:04 [sEVERE] [ForgeModLoader] The mod GalacticraftCore has attem
pted to register an entity ID 0 which is already reserved. This could cause seve
re problems
2013-08-16 15:09:06 [iNFO] [fml.ItemTracker] The mod MineFactoryReloaded is over
writing existing item at 102 (net.minecraft.block.BlockPane from Minecraft) with
net.minecraft.item.ItemBlock
2013-08-16 15:09:04 [sEVERE] [ForgeModLoader] The mod GalacticraftCore has attem
pted to register an entity ID 0 which is already reserved. This could cause seve
This seems to be your problem, one of the mods in your server.jar is scripted wrong where a entity ID value is already used, and is causing it to crash because it can't find that entity.
Please provide more information, what version of Tekkit are you using?
Also, does it crash when you go into a chunk, there could be possible map corruption involved
Now, From the post above, yes they are many variable that can cause a server to "Crash" now my question is when did this happen, What were you doing when it happend, if you loaded a new world does it still occur and does it say anything on screen when it crashes.
I would be happy to figure this out, but I need to first know that information.