Installing surround.vim plugin into Vim's plugins folder seems to have no effect?

I've downloaded the surround plugin (surround.vim) for Vim and installed it into the plugins folder. I know plugins work there as i've successfully installed the NERDTree and TList plugins.

Once surround is installed, i start Vim and enter insert mode i and type:

"Hello World!"

I then go to normal mode Esc and move the cursor into the text and 开发者_运维问答press cs"' and nothing happens!

I've also tried deleting the surrounds using ds and still nothing happens.

Have you any idea why this plugin is not working? Do i have to initialise it in the _gvimrc file? Could another plugin conflict with this one?

Any advice is welcome.

Thanks to sa125's answer i installed the Pathogen plugin manager and the troubles disappeared. It must of been something conflicting.