The error never poped up again.
I'm running on openmediavault (debian wheezy)
upgraded from openmediavault's plugin,
client chrome, all looks to work fine...
Except....
This is my Music folder tree...
Two weird things...
First I can't see the 2010 folder anywhere inside subsonic...
And the 2004 folder appears different than all the rest...
It is not related to folder permissions (I have quadruple-checked)
Noticed this first time after upgrade to Beta1 and still same with Beta2
(not sure if version 5 did the same, never noticed it)
Any ideas?
UPDATE
The 2004 issue was caused by a lonely mp3...
I renamed the 2010 folder, and that seemed to fix the issue...
So no issues for me except the missing Select All action...