JTEdit is extremely unstable, and chews through your sys resources almost as much as Doom3 ( well, ok, not quite as much, but you get the point ).
The only way I could get it to run on my family PC ( low end specs ) was to run it in compatability Mode for Win98, then close ALL open processes ( sometimes including explorer.exe ) then run JTEdit.
Also, if you do get it working, I suggest you save often, and in different formats ( .jtw is the most stable, others seem to lose or gain data randomly ).
Jess.

Team EOD :: Programmer/All-Round Nice Guy
Aust. Convention!