The jenkins build runner fails to complete when building my project under windows 8.1

It checks the project out from bitbucket fine, and runs fine until it gets to the 'used assets' list, at which point it just hangs and never completes.

Running the exact same parameters from the command line executes fine. The editor script that I'm executing also works fine when run from within the editor.

Will see if I can get it to reproduce with an example project...