/playdemo does not obey demo_dir when attempting to playback .qwz demos - it always takes the path relative to /qw.
demo_dir = "qw/demos"
qizmo_dir = "." (COMPRESS.DAT is present in Quake dir)
bla.qwz present in qw/demos directory
"/playdemo bla.qwz" gives "Error: Couldn't open bla.qwz"
Now move bla.qwz to /qw
"/playdemo bla.qwz" works fine
.qwd and .mvd appear to be unaffected by this bug
Ezquake 2.0.1 stable on Win7 64bit