Problem with gibbed tools

I have a version of Gibbed tools for DotP 2013. I can unpack WADs easy enough, but after I play around a bit and try to pack them, it doesn't work. The Gibbed.Duels.Pack is dated 19/11/2012.
I managed to find an older version of Gibbed tools with the equivalent exe file dated 18/6/2010 and this time it seems to work. Is there some explanation for this?
I managed to find an older version of Gibbed tools with the equivalent exe file dated 18/6/2010 and this time it seems to work. Is there some explanation for this?