exite code 1 - pls help

[Grunerkobold]

I tried to convert a custom model data texturepack for a minecraft server, on version 1.21.10 the pack is on 1.21.4 but it works in java.
when I try to convert the pack, the pack info always gets extracted but than the conversion fails and it says, that the process was completed with error code 1. Pls help!
here is the pack I tried to convert:
custom waffen 3D Schwert.zip