Yes, it is a simple as "perl peernode_file_051.pl" (or the name of one of the other perl peernode monitors)
If you want it to run in the background, though, you should turn off the verbose option and use "perl peernode_file_051.pl &"
You only get stats credit for the jobs actually submitted. If you have a fast computer, most of the jobs will be submitted before someone else has a chance to do them. The chessbrain supernode is slightly intelligent and sends what it thinks are bigger jobs to the faster computers (based on the benchmark when you first start up the client). Once you've finished your first job, the supernode gives you another one, which either hasn't been assigned yet, or was assigned but not returned. After a certain amount of time, based on the time remaining in the game, etc, the supernode replys abort when you try to submit it. This means that it has already made the next move, or that someone else finished your job before you.
It is somewhat related to the speed of your computer, but not entirely. Lets say you have a pretty fast machine. You finish your first job and submit it. Then you are assigned a second job that someone else is already working on. However, thier computer is only a little slower then yours, so they finish it first, and you end up with one submitted and one aborted. That person, though, has 1 submitted and 0 aborted. But, if someone's computer is very slow, like my P166, it will be aborted almost every time (95% or so for mine).
Of course, the above is derived from observing the clients behavior, writing the PNM, and reading the chessbrain forums, so it may be wrong, or at least shakey in some areas.