Unrelated to your perl problems that others have already pointed out, but here's a handy little trick:

Even if you do use grep on the remote end there's no need to run it twice. I don't remember where I found this originally, but if you include a character class with a single member you don't need to use the second -v invocation to weed out your grep process from ps results. E.g. for your example you'd do grep '[f]'irstbo; the brackets keep it from matching against the grep process in the results (since [f]irstbo can't match aganst grep [f]irstbo but does match the process you're looking for).