Rack Alignment Problems

I just recently picked up a server rack and some sliding rails to mount my equipment, however, I'm having some issues with my 4U NAS and the "recommended" rail kit for it. Specifically, once the box is racked it doesn't line up evenly on rack units. The result is that the rack unit above and the rack unit below the box cannot be occupied by another system, making for ugly gaps and reducing my useable space. The box is an iStarUSA 4U and the rails are the iStarUSA universal rail kit.

The...

Rack Alignment Problems