Loading data via PHP - timing

Hi Guys
I have a movie where the mouseover popups are populated by mysql data from a database. I have some actionscript on frame 1 that loads the data using sendandload and applies it to variables, in the dynamic text fields of the popups I have those same variables as parameters.
If you start the movie and wait a few seconds for the data to load, the popups work fine. But if you mouseover the popups as soon as the movie starts, before the movie has had time to load the data, the popups are blank, and they stay blank.
Whats the best way to handle populating text like this? Should I stop the movie until the data has loaded or is there a way to make flash continue to try and load the data?
By the way the popups are dynamic text fields that appear when parts of the movie are moused over, and my database retrival code is like this:

var popupData = new LoadVars();
popupData.onLoad = function() {