PHP errors after installation process

[Brian]

Hi there,
I've run into a series of errors that were simple to fix, and some I
couldn't. I ran into many instances of the warning that the

= &new

construct was deprecated - I fixed those.

When I try to login with the admin/demo credentials, I get this:

Fatal error: Call to undefined method AppModel::AppModel() in C:\xampp
\htdocs\jmp\admin\lib\jumper_lib\Auth\AuthPriv.php on line 54

I've uninstalled and reinstalled once, is there any alternative to
doing that again? I would need to fix the many cases of the problem I
mentioned above if I did that.

Thanks.

-Brian