Unable to install from zip file...please help

Hello there,

This is my first ever post, so please go easy on me! I've already done forum keyword searches, checked several FAQs and followed every online and YouTube tutorial I can find. All to no avail.

Very simply, I can't add a repo zip file, from 'System>Add-Ons>Install from zip file'.

I can navigate to the Home Folder fine; the repo file is displayed on screen, beneath the Application, Library & Media folders. The repo file in question is the Icefilms add-on: repository.googlecode.anarchintosh-projects

However, when I select the zip file, nothing happens. It doesn't install, and I just get returned back to the top of the folder structure. What I did notice at the bottom of the screen, is that there are OK, Cancel, New folder and Mirror Image options. Cancel is highlighted, and I am unable to change this. So I don't know if this 'Cancel' default is effectively cancelling the selection?

This is driving me mad, as i'm sure there's a very simple answer to this...I just can't work it out

Hope someone can help. Thanks in advance,
Marc