[Dredd]

Uninstall CLEO 4 and try again.
If the problem still occurs, try uninstalling SA-MP and GTA San Andreas and reпnstall them both in another directory as used before uninstalling (Most likely it's installed in C:\Program Files (x86)\Rockstar Games\Grand Theft Auto San Andreas - Just install it somewhere else, in another folder(for example C:\Program Files (x86)\GTA GAMES\Grand Theft Auto San Andreas))

EDIT: Or just try to remove the last mod(s) you added.