"File wasn't a zip file ()"

Trying to upload “Customizable Weaponry” 1.05 update, but it’s telling me that it’s not a .zip file, even though it is.

Get winrar.

That’s what I’m using.

Get 7zip.

Use Deflate for your encoding.

Try sending to .zip file folder instead of making a winrar ZIP file, if you are not doing so.

Check that it’s actually a .zip file and not a .rar