Show errors on inaccessible payload files

lib/msf/core/payload/stager.rb

@@ -188,15 +188,14 @@ def handle_connection(conn, opts={})
         end
       end
 
-      p = generate_stage(opts)
-
-      # Encode the stage if stage encoding is enabled
+      # Generate and encode the stage if stage encoding is enabled
       begin
+        p = generate_stage(opts)
         p = encode_stage(p)
-      rescue ::RuntimeError
+      rescue ::RuntimeError => e
         warning_msg = "Failed to stage"
         warning_msg << " (#{conn.peerhost})"  if conn.respond_to? :peerhost
-        warning_msg << ": #{$!}"
+        warning_msg << ": #{e}"
         print_warning warning_msg
         if conn.respond_to? :close && !conn.closed?
           conn.close

lib/msf/ui/console/driver.rb

@@ -364,7 +364,17 @@ def on_startup(opts = {})
 
     run_single("banner") unless opts['DisableBanner']
 
-    av_warning_message if framework.eicar_corrupted?
+    payloads_manifest_errors = ::MetasploitPayloads.manifest_errors
+
+    av_warning_message if (framework.eicar_corrupted? || payloads_manifest_errors.any?)
+
+    if payloads_manifest_errors.any?
+      warn_msg = "Metasploit Payloads manifest errors:\n"
+      payloads_manifest_errors.each do |file|
+        warn_msg << "\t#{file[:path]} : #{file[:error]}\n"
+      end
+      $stderr.print(warn_msg)
+    end
 
     opts["Plugins"].each do |plug|
       run_single("load '#{plug}'")