The we had a similar report from 2015 by a user who tried to use the Cg classes.
It turned out that the Nvidia provided Cg.dll and CgGL.dll installed on the system was 32bit and those system dll refused to get load using a 64bit JVM.
Previously it was possible to workaround this limitation by passing -d32 to the JVM however that option has been depricated and removed using Java 10.
Are 64bit versions of Cg.dll and CgGL.dll available?
It appears the cg-toolkit is depricated by Nvidia.