Lost music after iTunes sync

Hi,

I recently sync my iPhone and once it had finished uploading all the updaded apps I got a message stating that iTunes could not save the backup file.

The inital phone info page shows that I have no apps, photos or music installed. This is partly true. all apps, photos are fine, I have lost all my music & playlists!

I now cannot upload any music, a reboot of the iPhone does nothing!

Any suggestions to what I should do?

Thanks

Robin