By means of workflow action scripts, custom workflow actions can be created in order to execute complex logic in a single workflow action or to access elements (like sublists) not yet accessible to standard workflow actions. More information about workflow action scripts can be found in SuiteAnswers : Workflow Action Scripts.
Prerequisite is a workflow containing a custom workflow action (created by means of a workflow action script) which is triggered on a particular record. The scenario is that as soon as the custom workflow action is triggered the following error is displayed: "You do not have privileges to view this page". The error is thrown even when the workflow is executed by an Administrator role.
The reason for the error occurrence is that the workflow action script has been deployed (Deployment Status: Released) and therefore is accessible for the workflow to trigger it, however no Audience has been set. An audience can be set on the script deployment record in the Audience tab.