You really need to find some alternative folder icons. Other than that, a bit grey but a nice job! I particularly like your 'login', 'new topic' etc. buttons.
The text in the "CoasterFuel Networks News" table is way too big, while the links at the top of the pages are pretty small (and not exactly easy to read). And then the links at the bottom of the pages are big again... Try using font sizes that are closer together unless the text shouldn't be too "eye catching" (like copyright text, opposed to navigational links).
It looks pretty clean, but the background image is giving me a headache because it greatly reduces the legibility of the text put straight on the background.