Bumble Bee Snack

I came across this bumble bee struggling on the ground in the garden. I guessed it needed some sustenance so I gave it some maple syrup on a spoon. As you can see it seemed to enjoy it (there's some extra photos, and a short video of it lapping up the syrup, on flickr here) - but sadly it still seemed unable to fly. We placed it on some nice flowers in the hope that it would eventually be able to take off.

Does anyone know whether maple syrup is bad for bees? Or maybe it had something else wrong with it.