Seen it before, not the hardest thing to fix. Have ever deleted a file named "something".dll from gta sa? All you have to do is simply google it. We'll do bass.dll for an example, and it'll usually be the first link. Here is the trusted site I use. (This site is where I got bass.dll)
http://www.dll-files.com/dllindex/dll-files.shtml?bass
Then all you got to do is click Download Zip-File at the bottom and there ya' go! (This works for any .dll files that are damaged/accidentally removed or for whatever you need them for.)
http://www.dll-files.com
Or googling them is easier.