Ohhh, fuck.
If thats during installation, go get yourself a new GTA SA disk...that is what I had to do...
Though I tried some disk fixing things, and that worked a couple of times:
- Hold the readable side of the disk towards a UV lamp for a max of 30 seconds, about 4 inches away.
That worked for me the first time. Second time:
- Ran the disk under hot-ish water for about 10 seconds, and left it to try by sunlight by my window.
3rd time, none worked. I can still use the disk to run gta_sa.exe, but it won't install. I got a new disk.