I had a similar problem the first time I tried exporting a .swf file to Visual Studios. I had to make certain that I had a flash player installed in VS and everytime I open a new project I have to make sure that I have a path to the flash player established for the new project. What webbuiler program are you using? Make sure it has a flash player extension or you will probably continue to have that problem with your webbuilder software. Not all of them have built-in flash players... HTH