In order to get PAPI working on this machine you must setup a kernel with

 * options HWPMC_HOOKS
 and,
 * device hwpmc (or kldload hwpmc.ko)

 Additionally, for i386 systems you need:
 * device apic

See http://code.google.com/p/papi-for-freebsd/wiki/HowToInstall for further
details.