[Paraview] Error when adding Key Frame using Camera Track

[Michael Martinec]

I am trying to animate between different views of different *.vtu files 
(like volume representation with surface of slice plane). When I select 
Camera from Track Selection and want to add a key frame this error 
appears in the Output Messages dialog:


Invalid parameters to add link

Invalid parameters to add link

Invalid parameters to add link

Invalid parameters to add link

Invalid parameters to add link

Invalid parameters to add link

Invalid parameters to add link

Invalid parameters to add link

Invalid parameters to add link


What does it mean? How can I solve the problem?

Kind regards and thanx for helping.
*Michael Martinec