Just tried the ECC with Hybridfox 1.6 build 000024 and it works. You seem to be using the right endpoint URL (http://ecc.eucalyptus.com:8773/services/Eucalyptus/), but make sure you are using the right set of credentials.
I can login http://ecc.eucalyptus.com:8773/services/Eucalyptus/ using Hybridfox now , I get the err because I access http://ecc.eucalyptus.com:8773/services/Eucalyptus/ directly in the browser.
In ubuntu I can ssh -i myfirstkeypair.private root@173.205.188.140
I copied the file myfirstkeypair.private to the windows and login using putty, the error below appear.
Unable to use key file "E:\ec2-keys\myfirstkeypair.private" (not a private key)
Using username "root".
PuTTY Fatal Error
Disconnected:No supported authentication methods available