Can not find any existing php class

Hello guys,
A little of your help is required. I want to integrate FLEX with PHP and I am having issues doing that. May be there is some error in the flash builder but here are the details of what I did so far. I installed flash builder for zend and php and loaded a sample database already available in zend.
But when I tried to configure php service to connect it to that zend database, I couldn’t find any existing php class for the available data services. So I generated one using the flash builder. I entered my credentials correct but it encountered an error:
"Unable to connect to database using special connection information."
