Links to external classes

Hi,

Can someone explain how external classes run?

I donwloaded an external class and the linkage properties on my local system is
project.classes.scaleMe

Now when I upload to my remote serve the class does not work.

Is the class embedded into the swf and do I need to upload the external classes to my server?

Will the linkage address change from a local to a remote server? Or any other reason why it does not work?

Many thanks.