When using flash cs4, when you press Ctrl + enter to preview, an error message is often output, "the file" toplevel. As "required for checking the type of Action Script 2.0 cannot be found ". Make sure that the "$ (localdata)/classes" directory is listed in the Global class path of the Action Script's preferred parameter. I started to endure it, but I had to do Flash for some time. I had to handle n errors every day. I couldn't find a good solution on the Internet, so I had to solve it myself.
Method:
Open flash cs4, select Edit> preferred parameter, select the ActionScript item, and select ActionScript 2.0 to set ..., click "+", add a new path, enter C:/program files/Adobe Flash cs4/common/first run/classes, and set "toplevel" of Flash cs3. as "the file is copied to this path. It should be resolved now!
Toplevel. As download: (do not use the download tool. Visit this page and use a browser to download it .)
Http://cid-3d228983c0afaf80.skydrive.live.com/self.aspx/Documents/toplevel.zip