title: Prefix for element not bound
body: <p>I am a newbie in Flex development and using Flash Builder 4 with SDK 4. Now I get the error that "the prefix "fx" for element "fx:Style" is not bound" in line number 4.
  I searched for it, and it has sth. to do with namespaces, but I can not solve it by myelf.</p>
  
  <p>I have the file called "UserStory.mxml" in the directory "components" to place it via the main.mxml onto the screen:</p>
  
  <pre><code>&lt;fx:Script&gt;
      &lt;![CDATA[
          import components.UserStory;
          private function init():void {
              var userStory1:UserStory = new UserStory();
              userStory1.x = 100;
              userStory1.y = 100;
  
              userStory1.userStoryText = "test";
  
              this.addChild(userStory1);
          }
      ]]&gt;
  &lt;/fx:Script&gt;
  </code></pre>
  
  <p>The file in which the error occurs in line no. 4:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;mx:Canvas xmlns:mx="http://www.adobe.com/2006/mxml" width="300" height="150" styleName="userstory"&gt;
  
      &lt;fx:Style source="styles/styles.css"/&gt;
  
      &lt;fx:Text x="5" y="5" width="275" height="135" text="{userStoryText}" fontFamily="notes" fontSize="18"/&gt;
  
      &lt;mx:Script&gt;
          ...
      &lt;/mx:Script&gt;
  &lt;/mx:Canvas&gt;
  </code></pre>
  
  <p>Can someone tell me what's wrong?</p>