I get this error when I try to run either FO1 or FO2 and don't know how to fix it?

Either use the res patch or sfall. I'd vote for http://sourceforge.net/projects/sfall/, but I'm biased on account of being the author.

For sfall change graphics width/height in ddraw.ini to match your desktop resolution and set the graphics mode to 4. The res patch has similar settings.

Edit: Slight complications - if you've bought fallout 1/2 recently, then sfall will be included on the disc, but it'll be an ancient version that will break movies if you try using it, so either update it or get rid of it. Also the current version of sfall wont work with fallout 1, so you'll have to grab the res patch for that. I don't have a link off the top of my head, but you'll find it easily enough by searching NMA.

I just got them off steam yesterday.

I will try sfall, I already tried the res patch for FO2 but when I tried to use the res changer it said I had the wrong version and terminated it.