node_action_info() already defined

I get the following error after trying to install Workflow_NG:

Fatal error: Cannot redeclare node_action_info() (previously declared in /drupal_5/sites/all/modules/actions-5.x-2.0/actions/actions.module:1339) in /drupal_5/sites/all/modules/workflow_ng-5.x-2.x-dev/workflow_ng/workflow_ng/modules/workflow_ng_node.inc on line 183

I tried both the 5.x-2.0 and 5.x-2.dev versions and get the same thing.