Can't preapare build tools --> Doesn't look like a tar archive

Hi Mod Team

Yesterday I tried to set up my Ubuntu for some plugin development.
I managed to install all the dependencys, and cloned the mod-plugin-builder into my Ubuntu.
After that i tried to start the bootstrap.sh, but every time i did so it said:
“tar: That doesn’t look like a tar archive”, and suggested that my files are maybe corrupted.
But after cloning 2 more times i think my files are fine…

What do i miss?

Delete ~/mod-workdir and run bootstrap.sh again