Its on sale due to a promotion since the product is new. One other thing we did before deleting the WinFileCache.dat file was to reset the workspace. To do this, go to the Window->Workspace Layout->Reset '<current workspace>' menu in Dreamweaver. Then delete the WinFileCache.dat and see if the extension is working.
I'm not sure what you mean by a service tag, we would open a backend ticket too look into the issue in more detail if we weren't able to determine the issue through the forum posts.