I ran into a little error with Gibbed’s VPK extractor trying to work with L4D2. It would crash on a file every time and close the program.
I downloaded the source from his VPN and ran it in Visual Studio Web 2012. I soon found that there was an unhandled IO exception at the output stream part of Extractor.cs.
I added a small function to filter filenames and a try-catch block around the outputStream part. That way if it finds an invalid file it simply chugs happily along extracting the rest of the files.
You can also find the Fixed VPK Extractor 1.1 on Github.