Hi Erel, When usng the Hekkus Wrapper I created using the Legacy compiler in v6.01, there are no problems. However when used with the Optimized compiler, I get the following error: External compiler error Error compiling program. Error message: error CS0246: The type or namespace name 'hssNET' could not be found (are you missing a using directive or an assembly reference?) Line number: 17 Line: s1 = Speaker.SpeakerPlaySound(Sound1.SoundValue) OK How can I fix this from within my Library? Thanks.