From erricks homepage:
I imported a few songs, but then my Music Player said “No Music” and when I tried connecting to iTunes, it said it was corrupt and that I needed to restore
This is very unlikely to happen. However a few people had this problem, so that’s why I added an automatic backup feature on iSlsk v0.3 so that you can restore your music library if anything goes wrong when importing music. In order to restore your backup, you must be familiar with SSH, or with browsing your iPhone/iPod filesystem. If not, then search the net for tutorials.
You must follow these steps
1. SSH into your iPhone / open your file browsing program (I use WinSCP)
2. Browse to /private/var/mobile/Media/iTunes_Control/iTunes
3. There you should see 2 files named “iTunesDB” and “iTunesDB.bak”
4. Next delete the “iTunesDB” file
5. Rename the “iTunesDB.bak” to “iTunesDB”
6. Reboot your phone and you will have you music library back and iTunes will recognize it again.
errrick
If you didnt do a backup you may have to restore