Bluetooth shield zip file error

I cannot extract any of the Bluetooth Shield Demo zip files without getting an error:
End-of-central-directory signature not found. Either this file is not a Zip file, or it constitutes one disk of a multi-part Zip file.

I did download and extract NewSoftSerial10c.zip without error. Ideas?

No problems with File Roller.
Use open source software like 7zip -> 7-zip.org

Thanks for the suggestion Rony. 7zipwas able to handle it where WinZip choked.

Cheers from the Arizona desert.
John

I also use 7zip it is good compiler and organizer than Winzip.