Do you mean that the SWF files are not in the Library, or just that they do not work? 2 different problems, and different fixes..
If the Flash Library files are missing, it would be due to that Library file,
C:\Documents and Settings\YourUserNameHere\Application Data\Ulead Systems\Corel VideoStudio\12.0\VS_Flash.dat not being there or corrupt. To fix this you would need to reinstall or at least do a
repair install.
If those SWF files are in the Flash Library, but simply do not work, it may have to do with the
Flash.ocx file being corrupt. For some reason this seems to happen occasionally, and may have to due with other programs/applications that also use this file. They may even replace it with their version. This can be especially troublesome for those that use Flash authoring programs, like Adobe's Flash, SwishMax, or others. I do use the latter, and have had this problem jump up on more than one occasion. See
This Thread for instructions. Scroll down toward the bottom of that thread, and Steve has posted a link, where you can download a replacement flash.ocx file.