I get the following error when I run the game.

-----------------------------------------------------------------------
ERROR in
action number 1
of Create Event
for object objDevolver:

Error defining an external function.
-------------------------------------------------------------------------

If I click the abort button it the game will sometimes work but I never get any music. Sound effects such as punching work ok but no music.

Anyone know of any fixes or why this is happening?

It's a popular error.

Worth a try to:

Restart PC / restart game / reinstall game.

Do you have it updated to the latest patch?

It's common error due to the game engine's bug. Restart your PC, there's not solution as yet. It might re-appear randomly.