Problem with exporting

Hi there,

I am trying to export a swf but there is something going wrong. I have written my own class and stored it in a folder on my computer. By flash preferences this location is accepted and when I publish the movie the class is working. But when I open the html file with swf in it, the class is not working anymore. I dont know what to do since I never had this before and searches on internet did not gave any good result.