[SDL] Animation leaving behind a "Brighter" background?

[Adam Clauss]

I'm new to SDL and have been working through the tutorials on:
http://cone3d.gamedev.net/cgi-bin/index.pl?page=tutorials/gfxsdl/index

I have a basic app with a background and a single sprite that I can move
around w/ the arrow keys. However, for some reason it is leaving a 'streak'
behind it - as in the, the background is repainted correctly, but the
background is BRIGHTER than it was initially.

For the background, I am loading a bmp and then tiling that bmp onto another
surface (creating using SDL_CreateRGBSurface) to create the full size
background.

For an example, look here:
http://cabadam.homeip.net/streak.html

Adam Clauss
cabadam at houston.rr.com