Have you encountered this error message upon opening your InfoPath form in SharePoint 2010, including out of the box and custom workflow forms? Nothing to worry, you simply need to configure the State Service of your SharePoint Server.
The State Service Application is used by SharePoint Server 2010 for InfoPath Forms Services and other components to store temporary user session data. It is configurable through SharePoint 2010 Management Shell or Farm Configuration Wizards.
To configure the State Service using SharePoint 2010 Management Shell tool, as illustrated below, execute the following commands:
$serviceApp = New-SPStateServiceApplication -Name “<StateServiceName>”
New-SPStateServiceDatabase -Name “<StateServiceDatabase>” -ServiceApplication $serviceApp
New-SPStateServiceApplicationProxy -Name “<ApplicationProxyName>” -ServiceApplication $serviceApp –DefaultProxyGroup
To configure the State Service using the Farm Configuration Wizards, as illustrated below, simply launch the Farm Configuration Wizards and select State Service.
Hope this helps. Thanks.