Unable to update Project using QueueUpdateProject

Hi,

I have customized Ms Project Server 2010 to update certain custom fields on the check-in event of Project. The custom code checks out the project and updates the details using following method:

QueueUpdateProject(jobId,sessionId, myProject, validateOnly)

However, the project update doesn't work and following exception is thrown:

ProjectServerError(s) LastError=CustomFieldInvalidTypeColumnFilledIn Instructions: Pass this into PSClientError constructor to access all error information

   at UpdateProjectStoreInformation.ProjectListEventReceiver.ProjectListEventReceiver.ItemAdded(SPItemEventProperties properties)

   at System.Web.Services.Protocols.SoapHttpClientProtocol.ReadResponse(SoapClientMessage message, WebResponse response, Stream responseStream, Boolean asyncCall)

   at System.Web.Services.Protocols.SoapHttpClientProtocol.Invoke(String methodName, Object[] parameters)

   at UpdateProjectStoreInformation.ProjectWebSvc.Project.QueueUpdateProject(Guid jobUid, Guid sessionUid, ProjectDataSet dataset, Boolean validateOnly)

   at UpdateProjectStoreInformation.ProjectListEventReceiver.ProjectListEventReceiver.ItemAdded(SPItemEventProperties properties)

I am unable to debug this issue as no exception details are displayed. I am looking for some help urgently to resolve this issue. Any help in this regard would be appreciated.