I had a small problem with Flash in Firefox today - flash works - but no sound. I don't know what causes this error - but it seems to be fairly common. This problem only occurs in Linux systems with Firefox.
Fortunately, it was easy to fix. Before letting you know how to fix it, let me say that I use KDE on Fedora Core 5 Distro - I don't know how this solution will help people using other distros. So if you are using FC5, this is the solution...
- Open the KDE Control Panel.
- Find the 'Sound & Multimedia' Menu
- Choose 'Sound System' inside this menu.
- Click on the 'Hardware' Tab.
- Find the checkbox labelled 'Full Duplex' and make sure that it is OFF.
- Click on Apply - this should restart the sound system.
An image to make this more clear...
If all goes well, your sound should be working now.
If anyone knows the cause of these errors, please leave a comment.