I've installed the eco:drive on my 500, and have done 3 days of driving, 5 trips, uploaded in two batches, but for each journey eco:drive says that the fuel used is zero; which then means I have 'infinity mpg', and gives me an ecoindex of zero also.

It correctly reports the length of the journey and the time though.

Does anyone else have this problem or does anyone have any suggestions?

I think you need 5 separate days of data before it will start the evaluation. Either that, or you have the most economical 500 on the forum.