When copy and pasting from other sources on the web like webpages or forums, its a good idea to to first copy into notepad, then recopy the notepad code to your actual application. Very often you pick up some erroneous code or figures that may or not be visible to you, but generally notepad will eliminate that.
Alternately, could you not just make your own button and just change the URL to your .gif instead of the secured one at paypal?
or will it give a pop up error?
Karen