Soreento

My friend is having a similar problem as well since her Minecraft will sometimes close with an out of memory after a few minutes or after playing for 20+ minutes. I ended up disabling the Mapwriter mod on her computer since it only has 2 GB of RAM and 1 GB of RAM is being allocated to Minecraft. This seems to have fixed her out of memory issue for now. Your issue might be the Mapwriter mod as well since it does write the maps to your save directory as well as the single player worlds so it would be one of the folders that is being moved out of the Hexxit folder. Though the map would be regenerated so I wonder if the issue will still occur then.

PS. After more testing I think the crash in question is due to certain better dungeons templates. I'm not sure which ones but if I try to spawn a castles.prop in a snow area which ever random template the mod chose to use causes the internal server error.

I will create a separate post about this since your crashing issue sounds like mine, ie the crashing while wandering, minus the crashing when trying to log back in, I thought I would post what I have been seeing so you can test to see if the issue is the same. I have been noticing, from some very basic testing, that the better dungeons mod with Hexxit 1.0.5 causes an internal server error every time it tries to spawn a better dungeons castle or even the nether villages when I have my Hexxit server running on multicraft.jjservers.com, yet no one else is kicked out (3 people including myself) since they are in areas that we have already explored. Now what is interesting is when I run the same Hexxit server on my local machine running Windows I can wander all day long and not get a crash and the better dungeons structures are generated. The question is what is the multicraft server doing that is causing the generation issue? The multicraft server has 3 GB of RAM allocated to it too and is only using up 25% of the RAM as well. If you go in to creative mode and give yourself a castles.prop and then try to spawn it. I suspect you will crash out, but if you take the same server and start it on a Windows computer then try to spawn a castles.prop, your Minecraft will not give an internal server error. FYI - The server I am on is running a newer version of Java - INFO Java is Java HotSpot 64-Bit Server VM, version 1.7.0_21, running on Linux:amd64:2.6.32-358.0.1.el6.x86_64, installed at /usr/java/jdk1.7.0_21/jre