Can't open Admin panel - New Installation

I just installed OpenCart 1.4.9.3 on Windows 7 and IIS 7. I can't open the Admin panel, as I get a PHP error:

PHP Fatal error: Call to a member function get() on a non-object in C:\inetpub\wwwroot\store\admin\index.php on line 71

Does anyone know what this might be from? The index.php line is the 'if' command in the following:

Thanks for any help you can provide.

Sincerely,
Mark

OK. So, now I get the original login screen, but when I type in a username and password, the system appears to be logging in, but then no screen ever shows up. Then, if I reload the page, I get the error mentioned in my previous post.

Not sure what is going on. Any help would be greatly appreciated. Thanks!

>> New >> It now also appears that the store (not only the admin) has the same issue. The main page comes up, but nothing else works. And, then, I get the same error message again.

Mark

Did you use our search on this? I know that some had issues running on IIS. Why use IIS?