Welcome in 2015, the era of Multi-GHz Clocks, Multi-GB RAM, PetaByte storage and... 260 character path names.
Once again I was bitten by yet a random path length limitation on a win 7 64-bit platform with visual studio 2013. Of course I am aware that longer path lengths are supported on current windows platforms, provided you do some "\\?\" hocus pocus but Microsoft basically admits it's too much magic for them, given that they won't fix the random limitations embedded in their own build tools and just prefer to let hundreds (probably thousands) of developers bump into them.
More info about using long path names: