There's a bug with the soundtrack. At the end of chapter 1, the scene with Valerie in the park starts a sound track with chirping noises and such. This track never stops playing.
For a quick workaround, edit options.rpy and add
define config.developer = True
Then quit and relaunch the app. When you get the problem (whether by progressing in the story or by loading from a save file), just hit Shift-O, then type:
stop sound fadeout 5.0
and hit return. Hit escape to get back out of developer mode.