Your Win~1 (or the video driver, doesn't matter) does not fully support graphics programs running in a window. Configure your application to use VESA (or even better, standard VGA) modes, or run it from fullscreen, or ask Microsoft, in this order :-)
I think thats a little bit too easy. :)
I tried VESA and I tried VGA, all the same. But that Windows generally does not support graphics from DJGPP/RHide isn't true. If I use the Allegro Library all works fine, but Allegro is too oversized for me, I like GRX much better.
But there is something more wrong. If I used GRX two time within RHide, I cannot link anymore. The linker says "memory exhausted" and I have to end and restart RHide. That's really bad for developing. Also this problem doesn't occure with Allegro.
So I think somehow GRX does not clean up it's resources very good.
Thank you Thorsten