YOU ARE NOT INSTALLING THE SKIN CORRECTLY.
Do a search, this has been discussed many, many times. You need to see my thread on how to install a skin, although it was a Best Skins Ever skin [BSE]. They are the same product.
And be warned, we discussed this many times in other threads, ShieldZone does NOT warrant incorrect installation. Sounds like they are giving you replacements as a courtesy. Third time may NOT be a charm, so to speak.
I buy three sets of BSE skins for $21, shipped, but that is my preference rather than penciling out if the ShieldZone skin lifetime warranty really works out over time [there are limitations and with shipping charges may not work out in the long run. But like I said, that subject was hotly debated].
Now as to install, the spots are dust and debris. You are NOT installing it in a dust free environment. See my tip on the steamy bathroom [actually, it's BSE's tip]. While the skin may look fine when wet, any dust or debris will not show up until the skin dries. You need to look at the skin in an angle to see any dust.
You have to be super careful and my steps, while appearing anal, are necessary to assure a clean install. http://www.blackberryforums.com/gene...kin-pearl.html