[Wizwad]

I can't help but wonder if this isn't an idiosyncracy of the current Norton system. After all, if the .scr is merely an unzipped version of the .zip (which it clearly is) and the zip has been performed by an industry recognised package (which it has, namely Winzip), then it is baffling that Norton, which happily scans inside such zipped files/folders, would allow the zip through but not the uncompressed scr.

edit: beaten to it in a much more concise conclusion by Dale.