Force File Download, File Open Button

I have code written that when a user clicks a link, it opens a window that contains another aspx that writes a file's contents to the Response stream to force a file download.  When the file dialog opens, the Save and Cancel buttons work as expected, but the Open button does nothing.  It opens up whatever your default text editor is (i.e. notepad) like it should, but there's no file content in there.  ...however if you save the file and open it in a text editor, the file contents are there.   Is it something I am doing?  After poking around on the internet, I find others have had this issue too, but no solution.  FYI, I am using IE 6 if that makes a difference, and it opens the file successfully (I can see that when I step through the code - there are no errors - it can and does open the file and read the stream into the byte array - you know it's working anyway because if you click the save button on the file download dialog, it saves ...