Queue Job Status shows "Waiting to be processed" and then never completes

In Microsoft Office Project Web Access 2007, when you click Server Settings and then click Manage Queue, the Job State of jobs that are in the queue are displayed as "Waiting to be processed" and do not leave this state. You receive the following errors in the Event Viewer Application Log:

In Application log, we receive the following errors:

Standard Information:PSI Entry Point:
Office SharePoint Server
EventID 7757
Project User: <DOMAIN>\<user>
Correlation Id: ef47ace4-7aaf-44c7-99c2-241db1ea71bb
PWA Site URL: http://<servername>/PWA
SSP Name: <shared service provider name>
PSError: Success (0)
Queue System Restarting due to an unexpected error. Queue type (Project, Timesheet
queue etc): ProjectQ. Error: System.NullReferenceException: Object reference not
set to an instance of an object.
at
Microsoft.Office.Project.Server.BusinessLayer.Queue.BaseQueueAccess.SqlCallRetry.Ret
ryableSqlCallBase.ExecuteRetryableSqlCall()
at
Microsoft.Office.Project.Server.BusinessLayer.Queue.BaseQueueAccess.SqlCallRetry.Pur
geDeadReceiversSqlCall.PurgeDeadReceiversRetry(Int32 timeOut)
at
Microsoft.Office.Project.Server.BusinessLayer.Queue.BaseQueueAccess.PurgeDeadReceive
rs(Int32 timeOut)
at
Microsoft.Office.Project.Server.BusinessLayer.Queue.Receiver.PeriodicTasks()

==========

Standard Information:PSI Entry Point:
Office SharePoint Server
EventID 7761
Project User: <DOMAIN>\<user>
Correlation Id: ef47ace4-7aaf-44c7-99c2-241db1ea71bb
PWA Site URL: http://<servername>/PWA
SSP Name: <shared service provider name>
PSError: Success (0)
An unxpected exception occurred in the Project Server Queue. Queue type (Project
Queue/Timesheet Queue): ProjectQ. Exception details: Object reference not set to an
instance of an object.

Although there may be other causes for this error, this issue can occur when the SQL retry limit value is set to 0.

To resolve this problem, set the SQL Retry Limit value to the default value of 5 and then restart the Microsoft Office Project Server Queue Service. To do this, follow these steps:

1. Set the SQL Retry Limit value to the default value of 5. To do this, follow these steps:

1. On the Microsoft Office Project Web Access home page, click Server Settings.
2. On the Server Settings page, under Queue click Queue Settings.
3. On the Queue Settings page, change the SQL retry limit to 5.
4. Click Save.

2. Restart the Microsoft Office Project Server Queue Service. To do this, follow these steps:

1. From the server that is hosting Microsoft Office Project Server 2007, click Start, and then click Run.
2. In the Run dialog box that appears, type "services.msc" without the quotation marks and then click OK.
3. In the Services window, right-click Microsoft Office Project Server Queue Service and then click Stop. After the service has stopped, right-click it again and then click Start.