The file 03fz1 should have been at the location of 03ez1.
In all files, directories and references inside files '03fz1' has been replaced with '03ez1' manually (no arcGIS license at my disposal).
If arcGIS has issues loading kust2_2007_05 or parts thereof, this renaming might have caused this issue.
See ..\..\scripts\kust2_2007_05_03fz1_error.pdf