Wad editing issue with WadUpdater

Hi,

i'm having issues updating my cars wad file using Wadupater, it corrupts it everytime. If I extract the original wad using WadUpdated3.3 then repack it, I have an error in gpxpatch telling me wheels, mirrors, etc... cannot be loaded, though the appears in the contents of the file and the file size is identical to the original file.
I've tried using the latest version of wadupdater, but I have another issue: it removes the first letter of each folder of the wad, so the game cannot either find any file to load.

I'm back to using gp4master, which is quite less user friendly. Is there any way to have wadupater work properly ? Or any other tool that can build a wad from a directory, and keep the paths in memory ?