Thank you, I think that is the problem , though I don't know why it rised up suddenly. Actually I got through the problem following Borislav's advice.

>>I have an application which runs by years, but now, suddenly and without a reason it doesnt execute the "?? chr(7)" command.
>>If I run the app in debug mode it works but if I run it normally does not.
>>It is not something related with my PC because it gives the same error also on another one.
>>Any ideas ?
>>Alessio
>>
>>PS the set of instructions are something like this
>>
>>set bell to WaveFileName
>>?? chr(7)
>
>I ran into this some years ago. I think the reason is that some VFP controls don't accept chr(7) as a valid keyboard input. If one of these controls has focus when you issue that call, nothing happens.
>
>As others have pointed out, using an API call gives you more control.