almost all audio stopped working after i replaced a sound with a custom one

[dabmasterars]

after i replaced the sound (gunpickup2.wav) with a custom one in the "custom" folder, after going back to the game, the majority of all sounds failed to play. other sounds were replaced by their half-life 2 counterparts.

there was one unusual line in console: "Creating fallback sound cache"

fyi i'm making a map with some sounds replaced to fit the theme. (victory/failure sounds, pickup sounds)