Have you tried:
[url]http://localhost:8500/CFIDE/administrator/index.cfm[/url]

Oftentimes it will have better luck getting by whatever firewalls may be in
place, esp in a Corporate environment where 127.0.0.1 may be considered
(WebSense for one) an external IP.
If that doesn't work, start looking at your firewalls and don't forget Windows
now comes with one itself which should be disabled if you use a third-party
package.