I experienced this kind of problem frequently when my older computer was changing maps in GW, the cause was simply loading things during that time-frame where GW was loading. (aka, going to go load up a bunch of music or check a web page quickly while waiting for the game to load, yeah, even though it's like a few seconds)
Put simply, if you multi task at all, do
not do it when the game is loading between maps or areas.
This is when the game is most vulnerable to corruption. The other possibilities are generally when it loads anything, it can happen almost any time a player suddenly appears in the same map you are and your computer has to load it up.
Solutions:
- Do not multi task during loading screens etc, or ever while playing.
- Get a faster computer with 1.5GB+ RAM and/or a Dual Core processor to handle the load.
- Maximize GW and never alt+tab or switch out during a loading screen.
If it isn't anything like this, or simply happens even without doing anything on the side, I suggest that you post your system specs for others and myself to see to help figure it out.