Bleh. Can you remove all the blueprint stuff for that section, and start with a plain label and plain checkbox first?
See how those work by default, then start adding in the css and other elements until you can see what's not working.
I mean, by default a label will sit right next to a checkbox. In fact, it actually means it's a good idea to add whitespace somewhere. I add it inside the label.
<input type="checkbox" name="foo" id="foo" value="" /><label> TEXT</label>
is what you should get before CSS appears.