I replaced 4 icons in theme. Theme now fails to install

[AussieFries]

I replaced 4 icons in the Orion theme by Jasonevil. The icons have exactly the same name and same dimensions (48x48 / 60x60).

The APK won't install. I renamed it to zip and tried to install it in CWM. I the "check for signing" was disabled. This didn't work.

I have signed the zipfile with APKSigner from the Google Market but this didn't help either.

What do I do wrong?

 

[AussieFries]

Any ideas?

I use the Orion theme to make the status bar transparent.

Don't like the themed icons though.