I assume you are opening SA Cam Hack on new OS than Windows XP? Like Vista or Windows7?
You might get better help in this official topic:http://www.gtaforums.com/index.php?showtopic=225515&hl=
Download dx8vb.dll, and then put it in System32.
Then run CMD Prompt as admin, and type "regsvr dx8vb.dll"(with out quotes), and press enter. And you should get a confirmation message.