Unicorn.

It sounds like when you tried to do the first alteration you inadvertently removed something that should have stayed.

Blank pages and footers that become strange are usually a result of incorrect or missing PHP (or HTML) info.

If you PM me your server login details and your Zen Cart Admin details I can take a look for you.

The install is pretty straight forward.

Shoot me that info and I'll see what I can do for you.

:)