Warped boxes

[rottybee]

I just noticed some of the medium boxes I built have warped a little.  I have had them stacked in the basement since being built.  They sat on top of each other great when I first built them but now I notice a few of them have a gap between them.  In other words they "rock" from corner to corner.  Is this gonna be a problem?  The gap isn't very big, maybe 3/16".  I guess my concern is beespace and maybe another entrance for beetles? 
Evidently the wood wasn't so kiln dried when I got it!

[nella]

Set them outside on a flat serface with enough weight on top to twist them straight. Let
 the rain to soak them and after they dry they should be straight again. If nessary put a little shim under the low corners to over twist them.

[Michael Bush]

Set them on anything flat, including a bottom board.  Put a few concrete blocks on top...

[RayMarler]

It's more inconvenient for us keepers than it is for the bees. The bees will use the space or plug it. My guess is they'll use it if they can come and go through it. It's more a problem for us keepers as the boxes rock or tilt as we stack them up.

[doak]

You can take a wood rasp or a manual hand plane and even them up. Just don't take too much off, you can close the bee space up between the frames and the bees will weld the frames together. Or you can fold some paper to fill the cracks.
You may have gotten some damp or incomplete seasoned boards. :)doak