ProjectNodeConsistencyException

[veera sekhar kota]

I am getting this error when i am updating a project from the PSI Web SErvice
call. Can anyone tell me the reason for this error. I am not able to
replicate this problem too. It just happens for some projects at random and
when run again, they dont happen. It drives me crazy.
I am pasting the error XML that i got from the call
<?xml version="1.0" encoding="utf-16"?>

<errinfo>

<general>

<class name="Project">

<error id="9132" name="ProjectNodeConsistencyException"
uid="f3aeb5c5-7cff-49a8-bb96-2af9d5409110"

exception="System.ArgumentException: invalid call --- see comments in
code

at
Microsoft.Office.Project.DataEdit.Assignments.AssnCntr.XferRemainingWorkToActualWork(AssnNode assnNode, Double wrk)

at
Microsoft.Office.Project.DataEdit.Assignments.AssnCntr.SetAssnActualWork(Guid
guid, Double wrk)

at Microsoft.Office.Project.DataEdit.Obj.ProjCntr.SetData(Guid guid,
UInt32 pid, Object obj)

at Microsoft.Office.Project.DataEdit.Document.SvrDoc.SetData(Int32
entityID, Guid guid, UInt32 propertyID, Object obj)

at Microsoft.Office.Project.DataEdit.Document.SvrDoc.SetData(Int32
entityID, Guid guid, UInt32[] propertyID, Object[] obj)

at
Microsoft.Office.Project.Server.BusinessLayer.ProjectNodeConsistency.CheckNodeConsistency(AssignmentDataTable table, Boolean isRecalcCost)

at
Microsoft.Office.Project.Server.BusinessLayer.ProjectNodeConsistency.CheckNodeConsistency()

at
Microsoft.Office.Project.Server.BusinessLayer.ProjectMain.HandleProject(ProjectDataSet dataset, Guid projectUid, Guid userUid,

String userName, Boolean isNew, Boolean addColumns, ProjectLocks
projectLock, Boolean fCheckReadOnly,

Boolean fCheckProtectedActuals, Boolean fAllowAddEntRes, Boolean
fOptIndexRecalced)" />

</class>

<class name="Queue">

<error id="26000" name="GeneralQueueJobFailed"
uid="ae7f081e-1286-418c-9d35-d9951c6038fd"

JobUID="3877a97f-8a27-4b5f-96b3-1793f9b10cc8" ComputerName="FDXAPP114"
GroupType="ProjectUpdate" MessageType="" MessageId="" Stage="" />

</class>

</general>

</errinfo>