A lot of things can go wrong while uploading a file. For instance, it could be the case that you didn’t fill in all the required fields. Did you write a description? Have you added all your tags? Check all the fields once again and make sure you press the ‘save’-buttons from time to time. If you have done so, click ‘Upload Now!’ and your document is uploaded.
If that does not work, please try another browser, but don’t forget to log out on the browser you are currently using. If that does not work, you can contact us. Please explain the situation in detail and make sure to mention the name of the document you are trying to upload.