I've been testing the release candidates. rc1 through rc3 seem OK, but rc4 through rc6 all crash when I try to start them with my existing excrypted wallet:

$ ./bitcoin-qt
QGtkStyle was unable to detect the current GTK+ theme.

EXCEPTION: 11DbException
Db::open: Invalid argument
bitcoin in Runaway exception

terminate called after throwing an instance of 'DbException'
what(): Db::open: Invalid argument
Aborted
$

The exception is thrown by the "ret = pdbCopy->open(NULL, ...) in CDB::Rewrite() in db.cpp

I'm running a 64 bit archlinux, and am linking against package Berkeley DB ('db') version 5.2.36-2 because I couldn't find a version 4.

Is that likely to be causing this problem?

I'm pretty sure I had rc4 manage to open my wallet one time, but can't get it to work now.