diff --git a/app/views/dmsf_context_menus/_approval_workflow.html.erb b/app/views/dmsf_context_menus/_approval_workflow.html.erb
index ecdf46be..c3889e8b 100644
--- a/app/views/dmsf_context_menus/_approval_workflow.html.erb
+++ b/app/views/dmsf_context_menus/_approval_workflow.html.erb
@@ -31,21 +31,22 @@
         <% if wf %>
           <% assignments = wf.next_assignments(dmsf_file.last_revision.id) %>
           <% index = assignments.find_index{ |assignment| assignment.user_id == User.current.id } if assignments %>
+          <% assignment_id = (index && assignments && assignments[index]) ? assignments[index].id : nil %>
           <%= context_menu_link l(:title_approval), action_dmsf_workflow_path(project_id: project.id, id: wf.id,
-                                                                              dmsf_workflow_step_assignment_id: assignments[index].id,
-                                                                              dmsf_file_revision_id: dmsf_file.last_revision.id),
+                                dmsf_workflow_step_assignment_id: assignment_id,
+                                dmsf_file_revision_id: dmsf_file.last_revision.id),
                                 remote: true, class: 'icon icon-ok', id: 'dmsf-cm-workflow',
                                 disabled: !assignments || !index %>
       <% end %>
     <% when DmsfWorkflow::STATE_ASSIGNED %>
       <%= context_menu_link l(:title_start), start_dmsf_workflow_path(id: dmsf_file.last_revision.dmsf_workflow_id,
-                                                                      dmsf_file_revision_id: dmsf_file.last_revision.id),
+                            dmsf_file_revision_id: dmsf_file.last_revision.id),
                             class: 'icon icon-ok', disabled: !allowed %>
     <% when DmsfWorkflow::STATE_APPROVED, DmsfWorkflow::STATE_REJECTED, DmsfWorkflow::STATE_OBSOLETE %>
         <%# %>
     <% else %>
         <%= context_menu_link l(:title_assignment), assign_dmsf_workflow_path(id: project.id, project_id: project.id,
-                                                                              dmsf_file_revision_id: dmsf_file.last_revision.id),
+                              dmsf_file_revision_id: dmsf_file.last_revision.id),
                               remote: true, class: 'icon icon-ok', id: 'dmsf-cm-workflow',
                               disabled: locked || !workflows_available %>
     <% end %>