Hi A few comments here:
-You need at least 8Gig of memory to compile webkit
-First test that you uploaded the correct ssh key by doing an ssh to the server
e.g. ssh -p 29418 code.fairphone.com
-If you run into problems try building a pure AOSP (5.1) first (targeting the nexus for example)
-The emulator is no supposed to work (at least we never tried) and it is very uncommon to develop using the emulator. It is however possible to install the fairphone apps on any phone and emulator
Greetings