Error - AssignmentCannotEditSummaryTask when using QueueUpdateProject

[rceraso]

I am attepting to put together a web application to update selected project tasks on a Project Server 2007 installation. The code I am using is (for the most part) taken directly from the code example in the SDK under the QueueUpdateProject method. I am simply attempting to update the TASK_NAME field on one Task record on an existing project and nothing else. The problem is that upon calling QueueUpdateProject - I am getting error 135 - AssignmentCannotEditSummaryTask for what looks to be several Assignment records. The task I am updating is NOT a summary task. To further complicate things - this error happens even if I comment out the code that makes the change to the project DataSet (not updating the project DataSet at all). Here are the steps I am taking and the results I receive:

SCENARIO 1:

• read the project details using ReadProject - SUCCESSFUL
• check out the project using CheckOutProject - SUCCESSFUL
• update the TASK_NAME field - SUCCESSFUL
• call QueueUpdateProject - ERROR HAPPENS HERE

SCENARIO 2:

• read the project details using ReadProject - SUCCESSFUL
• check out the project using CheckOutProject - SUCCESSFUL
• call QueueUpdateProject (no changes to the project DataSet) - ERROR HAPPENS HERE

SCENARIO 3: (this Scenario works fine)

• read the project details using ReadProject - SUCCESSFUL
• check out the project using CheckOutProject - SUCCESSFUL
• check in the project using CheckInProject - SUCCESSFUL

And here is the actual code I am using:

protected void Button1_Click(object sender, EventArgs e)
{

q.Url = baseUrl + QUEUEWEBSERVICE;
q.Credentials = CredentialCache.DefaultCredentials;

Button Button1 = (Button)sender;
GridViewRow grdRow = (GridViewRow)Button1.Parent.Parent;
Label5.Text = grdRow.Cells[2].Text; //TASK_NAME field

int taskId = Convert.ToInt32(grdRow.Cells[8].Text); //TASK_ID field

int idx = grdRow.DataItemIndex;

//Get the Project ID from the GridView DataKeys collection
Label6.Text = GridView2.DataKeys[idx].Value.ToString();
Guid projectId = new Guid(GridView2.DataKeys[idx].Value.ToString());

Guid sessionId = Guid.NewGuid();
Guid jobId = Guid.NewGuid();

//Read the Project Details
WebSvcProject.ProjectDataSet projectDs = project.ReadProject(projectId, WebSvcProject.DataStoreEnum.PublishedStore);

//Check Out the Project
project.CheckOutProject(projectId, sessionId, SESSION_DESC);

//Update the Task field on the local DataSet
Label7.Text = "DS VALUE : " + projectDs.Task[taskId].TASK_NAME.ToString();
projectDs.Task[taskId].TASK_NAME += " Changed";

//Save the changes
project.QueueUpdateProject(jobId, sessionId, projectDs, false);
WaitForQueue(q, jobId);

// Check in the project
jobId = Guid.NewGuid();
project.QueueCheckInProject(jobId, projectId, false, sessionId, SESSION_DESC);
WaitForQueue(q, jobId);

}

I am VERY new to Project Server development so any assistance would be greatly appreciated.

Thanks in advance,
Rob