did your loading screen.tga had 512-512 pixels before convert it into .blp?
Yes.i assume it is properly imported into your map?
you have LoadingScreen.mdx (and you pointed your Map Loading Screen... to that imported file?) and your actual image for loadscreen target is: FullScreen.blp ?
some people see a WHITE screen? others see it?
that is odd, I would have thought a BLACK screen if it didn't load properly for them..
can you locate anything special about those who can't see it? do they have RoC and TFT? I dunno...something?
also, will it consistently not show for those people, or will it show the NEXT time they play?
I'd go with what ultimate11 said...
I've heard that even messing up the resolution by 1 pixel could screw things up.