Well I just installed the latest version of modernbill's demo to check out thier new features.
The problem is, after installation, I enter the admin username and password and am returned to the login page with a message stating that the login/password is invalid.
Now I made sure that everything was installed correctly (all requirements have been met) and even tried re-installing the script with no success.
I did have to delete the .htaccess files out of the /billing and /order directories because they were causing a internal server error. Im not sure if this has anything to do with the login process though.
Im not sure, but I think I had this same problem when I installed it over a year or two ago, but cant remember what I had to do to get this working.
If anyone has any ideas, please let me know!