It sounds like it's probably a minor fit niggle, or something to do with your gait (not a problem - just an individuality). Edit* of course, your gait will be entirely different running from how it is walking around the house. You're far more likely to be flexing your toes and using the big toe when walking. Maybe this is the issue?
I got really lucky with mine (wear women's 42 Bikila - I'm a guy). They give me far less blisters and rubbing than traditional running shoes. I found at first my left pinky popped out of the toe pocket occasionally: that foot is slightly shorter. As I wore them in, the fit got better and better. I've found VFFs to be much more robust than I expected, and I suspect they're going to last me far more than 500 miles of wear. Which is a good job at the price.
I do coat my toes up with Bodyglide before sliding into the shoes. You'll likely find that the shoes change shape and your feet adjust as you wear them more. As long as none of your toes are too long in the pockets - that rips VFFs to shreds extremely quickly.
The reason I would never recommend VFFs to another runner is because you have to be lucky enough that your foot and arch are pretty 'averagely shaped' in order to get a good fit. Did you have a chance to try yours on before you bought them, or did you do the arithmetic gymnastics and take a gamble ordering online?
Edited: 16/04/2012 at 12:33