What kind of sound are you using?
Is it a custom sound? If so, then you might have a sound formatting error.
Did you trigger your Ambient_Generic?
Usually problems with an Ambient_generic arize when you type in the correct path to the file. Do not use the browse thing to find the sound. I believe you have to type in the direction to the sound/ambience/sound.wav manually.
You also might have put your sound in the wrong folder.
Please give more information, and it would be a lot easier for me to help you