I've seen this on other posts, but I can't find a solution that works. Here's what I tried so far:
Running both Cube.exe and the cubelauncher.exe as administrator
Set compatability mode for both cube.exe and the launcher. Tried Windows XP (Service Pack 3), Windows XP (Service Pack 2), Windows 7, and Windows 8. Windows 8 doesn't throw the error if it's not run as administrator, but CubeWorld still doesn't run. Also, it does throw the error if it is run as administrator. Weird.
Unplugged my headphones
Uninstalled/reinstalled the game
Restarted Windows Audio in run > services.msc
Disabled speakers
Played around in advanced speaker properties
Just ran the new Windows update, so all of my drivers have been updated, as well as DirectX. Still the same error.
If anyone has any ideas, I'm all ears.
EDIT: I found the fix. If you are having this error, follow the following link:
http://www.microsoft.com/en-us/download/details.aspx?id=8109
Download the installer, and run the DXSETUP.exe that is extracted into the install folder. Works perfectly now.
One of my computers that has windows 10 works fine, two others I couldn't get it to work. I'm having problems with the directx drivers and this Audio error on windows 10 as well. I was unable to find a solution and gave up.