Their two primary mistakes were made long ago:
1. bidding too low on TheEVProject. They assumed site hosts would be happy to chip in $10-$15k to get a DC charger, which would vastly lower Ecotality's costs. They were way too optimistic on that point; and that really has stuck them in a very hard place - they can't find site hosts willing to pay, but can't afford to do installs without them. And they don't get the DOE money unless they are making installs. (DOE gets some of the blame for that, by not specifying oversight or penalties for failure to deliver in the contract. At least the DOE did tie payouts to installs; that helped a lot)
2. assuming they could quickly build their own hardware cheaper than they could buy known hardware elsewhere. They had originally applied using Chargepoint equipment. They built their own equipment cheaper...but after costs to fix software and hardware issues, it ended up being more expensive. (Again, the DOE could have specified that they use the hardware they applied with).