“An Error Has Occurred” while opening form in CRM 2011.

I was getting the following error while opening form of one of the entity (new_client) after upgrading the CRM server from beta version to RTM.

and inside application log

Exception information:

Exception type: NullReferenceException

Exception message: Object reference not set to an instance of an object.

at Microsoft.Crm.Application.Controls.AppNavigationBar.CreateOrderedAreas(NavPaneItems navPaneItems)

at Microsoft.Crm.Application.Controls.AppNavigationBar.ConfigureControl()

at Microsoft.Crm.Application.Components.UI.CrmUIControlBase.ConfigureControlInternal()

at System.Web.UI.Control.PreRenderRecursiveInternal()

at System.Web.UI.Control.PreRenderRecursiveInternal()

at System.Web.UI.Control.PreRenderRecursiveInternal()

at System.Web.UI.Control.PreRenderRecursiveInternal()

at System.Web.UI.Control.PreRenderRecursiveInternal()

at System.Web.UI.Control.PreRenderRecursiveInternal()

at System.Web.UI.Control.PreRenderRecursiveInternal()

at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)

The issue was we had commented some of the NavBarArea tag within the FormXml of the Entity.

<!–<NavBarArea Id=”Service”><Titles><Title LCID=”1033″ Text=”Service”/></Titles></NavBarArea><NavBarArea Id=”Marketing”><Titles><Title LCID=”1033″ Text=”Marketing”/></Titles></NavBarArea>–>

Uncommenting it and importing it again resolved the issue.

This was not creating issue for the beta version, however it seems that it won’t allow us to do that in the RC or RTM version.