Apply the theory of relativity...
Your compliment is good/bad, cute/confusing, etc. only based on the context of when, where, and how you said it, the sort of girl she is and the sort of guy you are.
Guys tend to freeze and say the funniest little things. Girls either stand there and wonder, think your creepy, or are aware that guys tend to experience brain freeze when in contact with slushies and hot girls. Which one is she. Only one way to find out, and that's to chat her up a little more. After all, it IS the neighborly thing to do. ;)
Complimenting her toe nails can tell her a few things. You're a foot fetishist (with a "note to self" to carry pepper spray), you're shy and had to look down at her feet (thereby noticing the toesies), you're smart enough not to fumble and say, "Nice boobs -- I mean shirt!" If you have the whole shy guy look going for you, you're pretty much safe. If you seem more like the confident guy who suddenly got brain freeze... Well, just try not to compliment her toes/shoes next time. ;)
You did fine. It's not you, it's the species. Besides, maybe she HAS adorable toes and works hard to keep them that way! Just remember to breathe evenly when she's around.