Try installing micrsoft C++ visual redistributes 2005, 2008 and 2012.
If that doesn't work then all I can say is you've installed it wrong, maybe. I mod GTA San Andreas myself and never had this problem.
If you can, try a clean reinstall of GTA San Andreas or if you can't do that then uninstall CLEO carefully by checking where all the files/folders went.
Then download and install CLEO from the original site which gives an auto installer and will also install ASI loader itself.
http://cleo.li/