Cannot assign variable. Please help!

This is frustrating. Here’s what happens…

I define my instance as msg1. It is a text box with Dynamic Text.

Then, I wrote the ActionScript as this:
var var1:String;
msg1.text = var1;

My code included this:
<param name=“movie” value=“card01.swf?var1=Testing1” />…
<embed src=“card01.swf?var1=Testing2” quality=“high” …

After compiling I still get the “Undefined” when run.

What did I do wrong?