[vtkusers] vtkAssignAttribute : Target location for the attribute is

[Mohammad Nazrul Islam]

Hi,
hope everybode is doing fine.I am trying to plot streamline using from structuredppoints and i have the following code. 

pl3d = vtk.vtkStructuredPointsReader()
pl3d.SetFileName("flow-00010000.-000.vtk")
pl3d.Update()


aa=vtk.vtkAssignAttribute()
aa.SetInputConnection(pl3d.GetOutputPort())
aa.Assign("OutArray","VECTORS","POINTS_DATA")
print aa
integ = vtk.vtkRungeKutta4()



line=vtk.vtkLineSource()
line.SetPoint1(12,0,12)
line.SetPoint2(12,4,12)

streamline=vtk.vtkStreamLine()
streamline.SetInput(aa.GetOutput()) 
streamline.SetSource(line.GetOutput())

streamline.SetMaximumPropagationTime(500)
streamline.SetStepLength(0.5)
streamline.SetIntegrationStepLength(0.05)
streamline.SetIntegrationDirectionToIntegrateBothDirections()
streamline.SetIntegrator(integ)
and the rendering staff.

but I am getting the following message.

ERROR: In/usr/local64/extra-packages/VTK-5.0.3/VTK/Graphics/vtkAssignAttribute.cxx, line 162
vtkAssignAttribute (0x86c8b0): Target location for the attribute is invalid.

vtkAssignAttribute (0x86c8b0)
  Debug: Off
  Modified Time: 207
  Reference Count: 3
  Registered Events: (none)
  Executive: 0x876d60
  ErrorCode: Success
  Information: 0x86c980
  AbortExecute: Off
  Progress: 0
  Progress Text: (None)
  Field name: (none)
  Field type: -1
  Attribute type: -1
  Input attribute type: -1
  Attribute location: -1

Code anybody help pls.


Thanks in advance,

Mohammad