Just a small correction to Dan's comments.
PF3 did NOT crash on either occasion.
FS either crashed or you shut it down without first disconnecting PF3(same thing to PF3). The first time PF3 displayed a nice error window and invited you to send in the relevant logs. This was due to FS presumably hanging and PF3 was unable to read the data it needed at that particular time. The second time FS simply disappeared so PF3 did not report an error as such but just said, oh well, FS has gone so I'm shutting down. PF3 logs were updated accordingly both times before it shut down itself.
Now, I would never say it's impossible, but I would say it's really, really, really, very unlikely that PF3 could cause FS to crash. We do not interact with FS directly and only do so via FSUIPC, using the various published memory offsets available.