Hi Arjun,
The reason the ERMS Workflow is not triggered could be because the user for whom the Workflow should be triggered does not have Authorization to execute the workflow.To check for Authorization goto Function Module SAP_WAPI_WORKITEM_COMPLETE,enter the Workflow Task ID and the user for which Workflow is not triggered and execute it.Check the Internal Table and if the message is User <username> doesn't have workflow authorization,there is Authorization Issue because of which WF is not triggered.