No problem reading as a user with admin privileges, but as non-admin I get:

com.sun.jna.platform.win32.Win32Exception: The system cannot find the file specified.
at com.sun.jna.platform.win32.Advapi32Util.registryGetStringValue(Advapi32Util.java:508)

Note this is reading from HKEY_CURRENT_USER, and I'm able to read through calling out to REG through Windows command prompt (from same Java process as gave the above error..).