VisIt could not read from the file "VISIT_TOP_DIR/test/junk.vtk".

The generated error message was:

There was an error opening VISIT_TOP_DIR/test/junk.vtk. It may be an invalid file.
VisIt tried using the following file format readers to open the file: VTK, Silo

If you know the specific format reader VisIt should use to
read this data, you can use Open As... (GUI) or
'-o <file>,<plugin> (CL arg.) and identify that specific reader
for VisIt to try. This will possibly give more information on
the exact error.