Can not save Forms !

Hi,

I've installed Obreaon on Apache Tomcat 8.
I can create forms correctly
When i click on "Save" button to save the form i get the following message :

"There was an error communicating with the database. Please contact the application administrator."

i've read and tryed this http://wiki.orbeon.com/forms/doc/developer-guide/admin/installing#TOC-Logging-configuration

Please Help !!

OS : Windows 7 x64

So if you enabled logging, is there anything in the logs? -Erik