Add more specific error output if a different gem set seems to be in use

Author: rastating

payloads/msfvenom_helper.rb

@@ -38,7 +38,14 @@ def generate_msfvenom_payload(mod, payload_name, *args)
 
     if stdout.empty?
       mod.emit_error 'Failed to generate the payload'
-      mod.emit_error stderr
+
+      if stderr.to_s.match?(/Bundler::GemNotFound/)
+        mod.emit_error 'WPXF and Metasploit are using different Ruby gemsets'
+        mod.emit_error 'If both packages are up to date, please report this via GitHub'
+      else
+        mod.emit_error stderr
+      end
+
       return false
     end