when i was getting this error, my VPN tunnel was up, traffic was passing normally. the unit i sent back for RMA would lock up at seemingly random times, and require a power cycle to recover. this started out as once a day, and eventually several times a day. that is the error i had logged on both ends of the VPN, the FG-60B (rma' d) and the FG-60. when it locked up, it could not be accessed by any interface, nor pinged....but on the other end of the VPN the FG-60' s sessions still showed open sessions, although no traffic was passing thru.
*note on the accessories i sent in that were not returned with new unit....support said the CSR who handled my RMA made an error instructing me to return the accessories and they are shipping me replacements. very quick solution to this by ForitNet' s support, thanks!