Hi,
the library does not compile (on linux) because etherShield.cpp tries to include EtherShield.h but the name of the file is etherShield.h (camelCase).
Ususally the C-header/source-files are in all lower-case so I suggest you rename the files to ethershield.h ethershield.cpp
or go with the classname EtherShield.h EtherShield.cpp
Eberhard