Can't upgrade from 1.0.2??

[duplay]

Greetings-

I have tried and read all threads about this but cant upgrade my CMSMS site from 1.0.2 to anything. I tried downloading the 1.0.3 version, copying and overwriting all needed files, adjusting permissions, and no luck. When I go to my site path mywebsite/install/upgrade.php I get the Internet Explorer message that the page doesnt exist.

If I go to mysite/install/install.php it does allow me to go to the install page with options. So install yes, but no upgrade.

I also tried downloading the 1.0.2-1.0.4 install and same steps, as well as the 1.1 version but no luck. I gave all accounts on my server FULL ACCESS to all just to make sure this wasnt a permissions issue.

Windows 2003 Server
PHP
MYSQL

Thanks