DVD playing

[Kevin C. Smith]

DVD playing stopped working today. Anyone else?
When playing Revolution OS, which is Region Free:

kevin at lappy:~ $ totem dvd://
libdvdnav: Using dvdnav version 1-rc5 from http://xine.sf.net
libdvdread: Using libdvdcss version 1.2.8 for DVD access
libdvdnav: DVD Title: REVOLUTION_OS
libdvdnav: DVD Serial Number: 2E448F61
libdvdnav: DVD Title (Alternative): REVOLUTION_OS
libdvdnav: Unable to find map file '/home/kevin/.dvdnav/REVOLUTION_OS.map'
libdvdnav: DVD disk reports itself with Region mask 0x00400000. Regions: 1
2 3 4 5 6 8
libdvdread: Attempting to retrieve all CSS keys
libdvdread: This can take a _long_ time, please be patient

libdvdread: Get key for /VIDEO_TS/VIDEO_TS.VOB at 0x0000012b
libdvdread: Elapsed time 0
libdvdread: Get key for /VIDEO_TS/VTS_01_1.VOB at 0x00001484
libdvdread: Elapsed time 0
libdvdread: Get key for /VIDEO_TS/VTS_02_1.VOB at 0x001c7702
libdvdread: Elapsed time 0
libdvdread: Get key for /VIDEO_TS/VTS_03_1.VOB at 0x001d0010
libdvdread: Elapsed time 0
libdvdread: Get key for /VIDEO_TS/VTS_04_1.VOB at 0x001db4ff
libdvdread: Elapsed time 0
libdvdread: Found 4 VTS's
libdvdread: Elapsed time 0

*** libdvdread: CHECK_VALUE failed in nav_read.c:356 ***
*** for dsi->dsi_gi.zero1 == 0 ***

Afterward playing clips on the harddrive I am unable to see the movie,
though sound works. Rebooting fixes this some of the time.
Thoughts?
-- 
Kevin C. Smith