Titanium SDK 3.1.0 [ERROR] TypeError: argument of type 'NoneType' is not iterable on building android app

Hi,

I´m trying to run an android app with Alloy framework and got this error:

[TRACE] Writing out AndroidManifest.xml
[ERROR] Exception occured while building Android project:
[ERROR] Traceback (most recent call last):
[ERROR]   File "C:\Users\Paulo\AppData\Roaming\Titanium\mobilesdk\win32\3.1.0.GA\android\builder.py", line 2528, in <module>
[ERROR]     builder.build_and_run(False, avd_id, debugger_host=debugger_host, profiler_host=profiler_host)
[ERROR]   File "C:\Users\Paulo\AppData\Roaming\Titanium\mobilesdk\win32\3.1.0.GA\android\builder.py", line 2264, in build_and_run
[ERROR]     self.manifest_changed = self.generate_android_manifest(compiler)
[ERROR]   File "C:\Users\Paulo\AppData\Roaming\Titanium\mobilesdk\win32\3.1.0.GA\android\builder.py", line 1404, in generate_android_manifest
[ERROR]     '-I', self.android_jar], warning_regex=r'skipping')
[ERROR]   File "C:\Users\Paulo\AppData\Roaming\Titanium\mobilesdk\win32\3.1.0.GA\android\run.py", line 38, in run
[ERROR]     print "[DEBUG] %s" % subprocess.list2cmdline(args_to_log)
[ERROR]   File "C:\Users\Paulo\AppData\Local\Titanium Studio\plugins\com.appcelerator.titanium.python.win32_1.0.0.1338515509\python\lib\subprocess.py", line 580, in list2cmdline
[ERROR]     needquote = (" " in arg) or ("\t" in arg) or not arg
[ERROR] TypeError: argument of type 'NoneType' is not iterable
[ERROR] :  Build process exited with code 1
[ERROR] :  Project failed to build after 9s 904ms

I'm on Windows 7 32bits and all the android SDK's are correctly installed and the emulator runs normally.

Can someone help me?

Thank you!