Maybe it depends on the size of the database. I am running svn-1586 on an NSLU2 with Debian and USB HDD and encountered the same problem sometimes. I have about 12K songs. Setting the rescan interval to 0 is what I did as a workaround as I do not add new songs more than once a week or so. You could install a tool like ‘htop’ and watch what’s happening during a rescan. If the slug starts swapping this might slow down the response time beyond the soundbridge’s timeout.
I just did a rescan while playing. The Connection broke during
(I have ~1K static .m3u playlists)
The physical memory limit was not exceeded, so maybe it’s just a performance issue of the XScale processor.