Job Processor error when creating dwf upon Check In of ipt, iam, or idw

[RobRidings2]

We've recently started working with Vault but appear to be having a problem when sending the dwf creation to the Job Processor during check in.  The Job Processor seems to work fine for other operations.

The following error is shown:-

Object reference not set to an instance of an object.

And from the Event Viewer;-

Error 2/20/2012 2:26:55 PM
Job 160 Autodesk.Vault.DWF.Create.ipt : Object reference not set to an instance of an object.
Exception: System.NullReferenceException: Object reference not set to an instance of an object.
   at DWFGenerator.InventorSelector.IsInventorLT()
   at DWFGenerator.InventorDWFEngine.IsSupportedFile(String fileFullName)
   at DWFGenerator.DWFCreateCenter.CreateDWF(String srcPath, String destDWFPath, ArrayList layoutList)
   at DWFGenerator.DWFCreateCenter.CreateDWFFile(String srcPath, Int64 inventorVersion, SourceDocumentTypeEnum docType)
   at Connectivity.Request.ExtensionHandler.Inventor.Internal.UpdateViewExtensionHandler.Connectivity.Request.Document.Currency.ExtensionHandler.IUpdateViewExtensionHandler.CreateDwfFile(RequestContext rContext, FileOperationRecord file, String workingFolder)
   at Connectivity.Request.Document.Request.ExtensionHandler.UpdateView.CreateDwfFile.Execute(RequestContext rContext)
   at Connectivity.Request.Common.CommonRequest`1.ExecuteRequest(RequestContext rContext)
   at Connectivity.Request.Runtime.RequestExecutor.Execute(IRequest req, RequestInstance reqInstance)
   at Connectivity.Request.Runtime.RequestExecutor.Execute(IRequest req)
   at Connectivity.Explorer.Document.ViewModel.UpdateViewContextExtensions.CreateDwfFile(UpdateViewContext context, FileOperationRecord file, String workingFolder, String publishOptionsXml)
   at Connectivity.Explorer.Document.ViewModel.UpdateView.CreateDwfImpl()
   at Connectivity.Explorer.Document.ViewModel.UpdateView.CreateDwf(Boolean& isCancelled)
   at Connectivity.Explorer.JobHandlerDwfPublish.InventorDwfJobHandler.Execute(IJobProcessorServices context, IJob job)

Thanks for any help in advance.