Based on the error description of "Illegal characters in path.", maybe a character used in the VPK files is an invalid file path character for whatever operating system or file system you are using. Crowbar expects Windows operating system using NTFS or FAT32 file system.

How very strange.
I have posted a screenshot of what the dlc3 folder looks like and what Crowbar shows for the VPK package contents. Maybe there is something different we can spot.
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=2981380753
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=2981382367

Crowbar 0.74 opens the mentioned VPK for me just fine.

Maybe the VPK files in the mentioned folder got corrupted.

Not sure if this will help, but make sure Garry's Mod is closed when trying to download from its workshop via Crowbar. Also, try using Crowbar 0.74, the latest Crowbar version.

Try setting "Override MDL version" to 48.

I am not sure what exactly causes this error, but the only time I ever saw the error myself was when Garry's Mod was open.

So, my only advice is to make sure Garry's Mod is not open.

New link:
https://sites.google.com/view/zeqmacawstidbits/tutorials/troubleshooting-missing-texture

Assuming there are duplicates to a decompiled QC file with no edtis, Crowbar would need changing so that it detects when a Crowbar-created animation uses the same name as an existing one.

As a workaround until then, a modder can delete one of the duplicates (probably always an empty one, i.e. one without any options).

Duplicate of: https://steamhost.cn/steamcommunity_com/groups/CrowbarTool/discussions/1/3325366198395558901