When automating the installation and configuration of Nintex workflow using the nwadmin tool cmdlet NWAdmin-exe-o-ConfigureSettings the error below is displayed in the command prompt:

Error Message: 
Command line execution error: Value cannot be null. 
Parameter name: Data Source 

 

Check the database section of the xml file being used for any invalid element. i.e.
The issue could be as a result of an error in the definition of the elements under ConfigDatabase in the xml file. Sample section of xml file:

<ConfigDatabase>
<Database >
<Server>SQLSERVERNAME</Server>
<DatabaseName>NintexWorkflowDB_Config</DatabaseName>
<UseIntegrated>true</UseIntegrated>
<Username>User</Username>
<Password>Password</Password>
</Database>
</ConfigDatabase>

The issue lies within the <Database> elements which should not exist as defined in the NintexworkflowSetup.xsd. The presence of the <Database> elements makes the nested elements unreadable effectively causing the error. The valid definition for the Config Database should be as follows.
<ConfigDatabase>
<Server>SQLSERVERNAME</Server>
<DatabaseName>NintexWorkflowDB_Config</DatabaseName>
<UseIntegrated>true</UseIntegrated>
<Username>User</Username>
<Password>Password</Password>
</ConfigDatabase>