Making AS3 wait for a couple of seconds

Hello,
I’m rather new to AS3 and have been tasked with a project, the project requires reading in values from an XML file created by PHP, this works fine if the XML file is available, and is just being updated by PHP, however, when flash calls the PHP page that creates the XML file for the first time, it doesn’t give PHP enough time to make the XML file.
Therefore, I need AS3 to hold on for a second or two, then try and load the XML file…
Thanks,