What are you doing to get this error message?:
HTTP Error code 404 file not found.
Is the file you are browsing to in the correct location on the remote server only a 404 error means that it is NOT and can't be found were the url says it is.
Also personally I would advise that you set up a local testing environment on your computer using XMAMP of MAMP depending on if you're using pc or mac. These are self-contained packages which are freely downloadable. You can then set up a local testing environment.