Hi Kazem,
an alternative route is to create a file containing the points and store the ellipsoid matrix of corresponding to each point as a tensor. ParaView will then be able to create an ellipsoid centered on each of your points. The tensor values will define orientation and the axes of the ellipsoid. This should solve the issue of visualizing many of them.
For example :
Attached is the corresponding file
ellipses.vtk (174 Bytes)
The expected format of the matrices is described here