Index: source/Commands/CommandObjectThread.cpp
===================================================================
--- source/Commands/CommandObjectThread.cpp
+++ source/Commands/CommandObjectThread.cpp
@@ -1183,8 +1183,8 @@
           thread->GetStackFrameAtIndex(m_options.m_frame_idx).get();
       if (frame == nullptr) {
         result.AppendErrorWithFormat(
-            "Frame index %u is out of range for thread %u.\n",
-            m_options.m_frame_idx, m_options.m_thread_idx);
+            "Frame index %u is out of range for thread id %" PRIu64 ".\n",
+            m_options.m_frame_idx, thread->GetID());
         result.SetStatus(eReturnStatusFailed);
         return false;
       }
@@ -1201,9 +1201,8 @@
 
         if (line_table == nullptr) {
           result.AppendErrorWithFormat("Failed to resolve the line table for "
-                                       "frame %u of thread index %u.\n",
-                                       m_options.m_frame_idx,
-                                       m_options.m_thread_idx);
+                                       "frame %u of thread id %" PRIu64 ".\n",
+                                       m_options.m_frame_idx, thread->GetID());
           result.SetStatus(eReturnStatusFailed);
           return false;
         }
@@ -1279,13 +1278,13 @@
         new_plan_sp->SetOkayToDiscard(false);
       } else {
         result.AppendErrorWithFormat(
-            "Frame index %u of thread %u has no debug information.\n",
-            m_options.m_frame_idx, m_options.m_thread_idx);
+          "Frame index %u of thread id %" PRIu64 " has no debug information.\n",
+          m_options.m_frame_idx, thread->GetID());
         result.SetStatus(eReturnStatusFailed);
         return false;
       }
 
-      process->GetThreadList().SetSelectedThreadByID(m_options.m_thread_idx);
+      process->GetThreadList().SetSelectedThreadByID(thread->GetID());
 
       StreamString stream;
       Status error;