Lol....-.-
That ocurrs becaue you .mpq warcraft 3 archive is corrupted. Reasons:
1. You maybe had used hacks, bots or tools and modified the .mpq archive badly.
(Try to use tested hacks, not all hack that you get)
2. You downloaded too many custom maps and some of them requiered to open some code source from .mpq file and that messed up your war3.
3. Doen't matter what comp u have or what video card u use. Because if you can play and you don't lag, then all its OK.
Ex: I played a Tower Map under 32x and after 2h or more, I minimized war3, to watch a internet page. When I maximized back, the screen was black with white lines. But nothing happened (erros), just needed to restart war3, because my video card was going to blow up :P.
So, you CAN'T get that error, because u play too much, or ur PC is at 100%.
That error 90% times comes from the .mpq file, because its damaged or corrupted.
Solution:
Reinstall War3