If you look at the sticky at the top of this board you will see that a 3002 is:
#define RUNTIMEERROR_SOUNDLOADFAILED 3002
It usually means a sound file you use in your level has not been copied over into the standalone. GG is a bit annoying with this sort of thing, even to the extent that if it told you which audio file it was in the error message it would be a lot easier to sort
Check your audio files in use for your map and likely one or more won't be in the corresponding standalone folder - copy it over manually and standalone should work for testing.
Any sounds you use should be placed in a map entity sound slot to make sure it gets picked it up, encrypts and copies over to standalone. Any sounds you reference directly to folder without doing this aren't picked up by the standalone build process yet.
Cheers.