Google App Engine not reading my environment variables

Google App Engine not reading my environment variables

I'm trying to set up GAE but dev_appservery.py exits with the following
message
Traceback (most recent call last):
File "C:\google_appengine\dev_appserver.py", line 184, in <module>
_run_file(__file__, globals())
File "C:\google_appengine\dev_appserver.py", line 180, in _run_file
execfile(script_path, globals_)
File
"C:\google_appengine\google\appengine\tools\devappserver2\devappserver2.py",
line 727, in <module>
main()
File
"C:\google_appengine\google\appengine\tools\devappserver2\devappserver2.py",
line 720, in main
dev_server.start(options)
File
"C:\google_appengine\google\appengine\tools\devappserver2\devappserver2.py",
line 695, in start
self._dispatcher.start(apis.port, request_data)
File
"C:\google_appengine\google\appengine\tools\devappserver2\dispatcher.py",
line 160, in start
_module, port = self._create_module(module_configuration, port)
File
"C:\google_appengine\google\appengine\tools\devappserver2\dispatcher.py",
line 230, in _create_module
_module = module.AutoScalingModule(*module_args)
File
"C:\google_appengine\google\appengine\tools\devappserver2\module.py",
line 913, in __init__
allow_skipped_files)
File
"C:\google_appengine\google\appengine\tools\devappserver2\module.py",
line 418, in __init__
self._module_configuration)
File
"C:\google_appengine\google\appengine\tools\devappserver2\module.py",
line 176, in _create_instance_facto
module_configuration=module_configuration)
File
"C:\google_appengine\google\appengine\tools\devappserver2\go_runtime.py",
line 104, in __init__
self._module_configuration)
File
"C:\google_appengine\google\appengine\tools\devappserver2\go_application.py",
line 69, in __init__
self._arch = self._get_architecture()
File
"C:\google_appengine\google\appengine\tools\devappserver2\go_application.py",
line 94, in _get_architectu
for platform in os.listdir(os.path.join(_GOROOT, 'pkg', 'tool')):
WindowsError: [Error 3] The system cannot find the path specified:
'C:\\google_appengine\\goroot\\pkg\\tool/*.*'
I have GOROOT set to C:\Go in my environment variables and in my PATH I
have C:\Go\bin
Why is GAE just not reading those values and how can I fix this?
I'm using GAE 1.8.3, Python 2.7.5 and Go 1.1.2.