I think I've found a little bug here.

Using the deb for 6.5b1 (from 2006-06-19), browsing by artist. slimserver is installed on a kubuntu dapper server, accessing it via konqueror on a kubuntu KDE desktop.

While browsing by artist, the following letters are off by one when they're clicked:
C
G
M
R
U

ie: Clicking on C puts you at the first artist starting with D; G puts you at H; etc.

Browsing by album seems displays similar behavior, tho with different numbers/letters: A sends me to the first album starting with B. 

Here's a pattern I just discerned:
Album: A is the 6th item in the list (1-2-6-8-9-A).
Artists: C is the 6th item in the list (1-2-3-A-B-C).
A puts me at B; C puts me at D.