VMBuilder.exception.VMBuilderException: '2' is type <type 'str'>, expected int.

Hi

with --cpus 2 on the vmbuilder command args, I get:
2010-02-24 18:58:45,579 DEBUG : Loading plugins
2010-02-24 18:58:45,586 DEBUG : ['dpkg', '--print-architecture']
2010-02-24 18:58:45,589 DEBUG : amd64
Traceback (most recent call last):
  File "/usr/bin/vmbuilder", line 24, in <module>
    cli.main()
  File "/usr/lib/python2.6/dist-packages/VMBuilder/contrib/cli.py", line 74, in main
    hypervisor.set_setting(option, val)
  File "/usr/lib/python2.6/dist-packages/VMBuilder/plugins/__init__.py", line 254, in set_setting
    self.context._config[name].set_value(value)
  File "/usr/lib/python2.6/dist-packages/VMBuilder/plugins/__init__.py", line 210, in set_value
    self.do_check_value(value)
  File "/usr/lib/python2.6/dist-packages/VMBuilder/plugins/__init__.py", line 177, in do_check_value
    self.check_value(value)
  File "/usr/lib/python2.6/dist-packages/VMBuilder/plugins/__init__.py", line 226, in check_value
    raise VMBuilderException('%r is type %s, expected int.' % (value, type(value)))
VMBuilder.exception.VMBuilderException: '2' is type <type 'str'>, expected int.

Bye

ProblemType: Bug
Architecture: amd64
Date: Wed Feb 24 18:59:14 2010
DistroRelease: Ubuntu 10.04
Package: python-vm-builder 0.12.0-0ubuntu1
PackageArchitecture: all
ProcEnviron:
 LANGUAGE=fr_FR.UTF-8
 PATH=(custom, user)
 LANG=fr_FR.UTF-8
 SHELL=/bin/zsh
ProcVersionSignature: Ubuntu 2.6.32-14.20-generic
SourcePackage: vm-builder
Uname: Linux 2.6.32-14-generic x86_64