I'm not sure if you are experiencing a server configuration issue or if there is a problem with the files you are uploading, or if the settings you have used in the wizard are not correct for your server. You will need to determine what the error is that is occurring first before you will be able to determine why it is happening.
I think it might be best to make a small test page for the uploading. You should create a page and add a form to it that has only a file field and a submit button. Make sure that you set the method to post and the enctype to multipart/form-data. Next apply the upload file server behavior to this page, make it very simple, just select the location to upload to and set the trigger to submit button pressed. Then you should expand the global upload bindings to drag and drop the debug info onto the page. When you are ready to test this make sure to test it with a very small file then check what the debug info says and look for the file on the server. Please post back with the results of this test.
