Thanks for posting!
Let's check the Admin Console > FileMaker Overview > Databases section. Does your database have blue checks in the PHP, XML, or XSLT columns (really, it only matters which ones you are using)?
Open the database locally in a copy of FileMaker Pro. Go to manage > accounts and privileges > Privilege Set tab > highlight a privilege > click on 'Edit'. Make sure that PHP, XML, or XSLT are checked in the Extended Privileges section. Repeat the process for any other Privilege Set you wish to have access to your database.
Aside from that, how many concurrent users would you estimate are connecting to your database?
Let me know how it works out.
Thanks for the help. That fixed the problem.