I've a little information to share about this! You had no reason to delete PowerISO. It was showing the association because it was your default programme to zip, unzip compressed folders. I understand your frustration but some programmes like these, never interfares with steam games.
Now, just a question! Did you try the blobset creator without txpk editing? I got that working though. The only sacrifice you'll have to make here, is the boundary ropes will be default. You can change pitch ads inside stadium editor with downloaded stuff from community. May be you'll try it without txpk