I bought a Super Sniper not too long ago (SS16x42). I seem to have a problem bringing it into focus: I have the parallax adjustment set to just under or at 100m (shooting at 100yd targets) and the bullseye is a bit blurry. If I set the parallax at about 175-200m, the image is crisp and clear.

I occasionally wear glasses, but it doesn't seem to matter if I use them or not... either way the scope is out of focus at the correct range setting and in focus at the longer range setting.

Is the ocular lens supposed to be adjustable... the section that has the - . + markings?

Is it supposed to turn? If so mine is very tight and I don't want to force it.

Yep, it turns!  The parallax gives you coarse focus, the ocular gives you custom fine focus.