Can't Connect with Apple Store

I'm trying to connect with the Apple STORE, to purchase a download of the upgrade from Lion to Mountain Lion.

Every time I try to connect by hitting "Download Now" I get the following error message:

"Firefox doesn't know how to open this address, because the protocol (macappstores) isn't associated with any program. You might need to install other software to open this address."

????????

I need to by SOFTWARE to buy an OS upgrade from Apple????

Any ideas what's going on?

Thanks

It doesn't mention anything about buying other software.

Try setting Safari as your default browser and try again.

And you would not purchase Mountain Lion in a web browser at all.

In Lion, you will need to open the "App Store" application found in your "Applications" folder in order to purchase and download ML.