Build Titanium mobile from source - Android SDK issues

Following the answer here to build from the GitHub source.

I have my class paths all correct as stated here

Upon running Scons I get an error stating that Android SDK is missing, when it is installed and working (OS X 10.6)

scons: Reading SConscript files ...
Exception: No Android SDK directory found:
  File "/Users/jmw/src/titanium_mobile/SConstruct", line 79:
    sdk = AndroidSDK(ARGUMENTS.get("android_sdk", None), 4)
  File "/Users/jmw/src/titanium_mobile/support/android/androidsdk.py", line 42:
    raise Exception('No Android SDK directory found')

#Android
export PATH=$HOME/Dev/Android/android-sdk-mac_86/tools:$PATH
export PATH=$HOME/Dev/Android/android-sdk-mac_86/platforms/android-3/tools:$PATH