I'm sure this has been an issue that's been asked of plenty of times. I took a look at the DOS feedback while I tried installing one of the drumkits via the import function, and I noticed that the error revolves around this message in DOS:
" 'C:/Program' is not recognized as an internal or external command. "
The issue here I believe is that DOS isn't recognizing the space in "Program Files" (kind of a duh here), so users that are experiencing the error "There was an error importing the SoundLIbrary" will probably have more success installing Windows Hydrogen in a folder that DOES NOT contain spaces. Picky little program, it is. :p