WinStore - Visual Studio Command Exited with Code 1

Hi,

I have a very simple project which works fine, except when I try and compile it after building for windows store. When I build with VS2013, I get the following error. I don't really see how "echo" can fail... any ideas on why this is happening? Thanks!

 Error    1    The command "echo UnityInstallationDir 'C:\Program Files (x86)\Unity\Editor'
 echo UnityProjectDir 'C:\Users\Dave\Documents\UnityProjects\Dribble'
 echo Copying assemblies...
 copy /Y "C:\Users\Dave\Desktop\Builds\Dribble_WinStore\Dribble\Unprocessed\*" "C:\Users\Dave\Desktop\Builds\Dribble_WinStore\Dribble\"
 echo Running AssemblyConverter...
 "C:\Program Files (x86)\Unity\Editor\Data\PlaybackEngines\MetroSupport\Tools\AssemblyConverter.exe" -platform=wsa80 "C:\Users\Dave\Desktop\Builds\Dribble_WinStore\Dribble\\Assembly-CSharp-firstpass.dll" "C:\Users\Dave\Desktop\Builds\Dribble_WinStore\Dribble\\Assembly-CSharp.dll" "C:\Users\Dave\Desktop\Builds\Dribble_WinStore\Dribble\\P31RestKit.dll" "C:\Users\Dave\Desktop\Builds\Dribble_WinStore\Dribble\\UnityEngine.dll" "C:\Users\Dave\Desktop\Builds\Dribble_WinStore\Dribble\\WinRTLegacy.dll"
 echo AssemblyConverter done.
 " exited with code 1.    Dribble