Generate XML data on the fly for use in Flash

I have a php script that generates an XML file (a list of photos) from a mySQL database. I want to kick off this script every time a visitor wants to browse the photos. Note that I don’t need to read the data in at this point, I just want the script to run so that my XML file will be refreshed with the latest data. I then have my photo display component read the file to display the pictures. I’ve tried loadVars(), loadVariables() and getURL() with no success.

As info, the php script runs fine on it’s own and does generate a good XML file if I run it manually.

Thanks in advance!