Everything that is printed in AX 2012 is using SQL Server Reporting Services (SSRS). It does this by connecting to AX when it is told to and gets the data. To find the settings for the AX Server it normally uses the default client configuration. In some cases (especially when you have multiple instances) this fails or SSRS is using the wrong configuration.
You can help SSRS by saving the correct configuration in C:\Program Files\Microsoft SQL Server\MSRS12.MSSQLSERVER\Reporting Services\ReportServer\bin with the name Microsoft.Dynamics.AX.ReportConfiguration.axc
Have a nice day
/Johan