You might want to take a look at this discussion on the Processing forum: http://forum.processing.org/two/discussion/3567/joysticks-in-processing-procontroll-library-help
Which includes this quote by user quark:
You can download the native libraries for Windows 64 bit (jinput-dx8_64.dll) from here.
Put this with the other jinput files and rename it jinput-dx8.dll (replacing the existing file for 32 bit Windows), I tried this in Windows 7 (64 bit) with Processing 2.1.1 and it worked for me.