There are hundreds of threads like this, if you would just read one you would get your answer. But anyway, you probably have Version 2 of San Andreas, and Version 2 doesn't allow mods, so you need to download the downgrader patch (From Here). Open the Folder, and run the application to downgrade to Version 1. If you have installed the Mods in SAMI, you shold be ready to go, but if you have used the IMG tool, you need to make sure that you have rebuilt the Archive. (Comands>Rebuild Archive).
If you have used IMG and they still don't work, you will have to replace them with the original, so always make backups. If you didn't make backups and it doesn't work then you will have to uninstall San Andreas, Permanantly delete, San Andreas folder, and also the "Hidden" San Andreas folder - My Computer> C Drive> Program Files> Rockstar Games> San Andreas delete both of those folders, delete them from your recycle bin and re-nstall San Andreas, thats why I reccomend using SAMI for Mods, as it automaticlly makes a backup which can be Re-Installed at any time
Thanks Butters but i got the gane to work myself
i just forgot that in SAMI has the Uninstall option xD
