The procedure should be
1. click browse button. a popup will open where you can select the file.
2. when you click open, a file path will be placed in the textbox.
3. click the submit link to upload the file.
Make sure you have the proper language file elements to the language file if your default language is not English.
If you followed this procedure and yet no file is uploaded, then there is some problem with the xls file you are uploading. You can then post the xls file here.