'module' object has no attribute 'check_output'

I am getting the following error while trying to execute the indexing test:

[2013-05-21 14:48:46,236] IdxTestSetup: Splunk restarted successfully [2013-05-21 14:48:46,237] IdxTestSetup: Adding file monitor for the static dataset to be indexed [2013-05-21 14:48:46,240] IdxTestSetup: Waiting for indexing to finish [2013-05-21 14:48:46,241] IdxTestSetup: Using datagen record - looking for 183729363 events in the splunkit_idxtest index Added monitor of '/ssd1/splunkit/splunkit-server/data/static'. [2013-05-21 14:49:16,270] IdxTestSetup: Exception - Terminating setup. Detail: 'module' object has no attribute 'check_output'

Any help is appreciated.

Thanks Martin