Importing custom classes

programming flash
1

Okay I am having an issue getting my custom made classes imported to the flash movie. It seems to ave a problem importing (or using) the class. Here is the as code I am attempting to use to import and call to a function inside of a class:

import form_classes.as;
var Contr:Controller = new Controller("testt");

It always pops up an error of

**Error** Scene=Scene 1, layer=Layer 1, frame=1:Line 3: The class or interface 'Controller' could not be loaded.
     var Contr:Controller = new Controller("testt");
Total ActionScript Errors: 1   Reported Errors: 1

and I am not sure why. So if anyone could help me out here that would be great.