setting preferences in Sunbird

["Steven M. Bellovin" <smb%cs.columbia.edu@localhost>]

I'm having trouble setting preferences in Sunbird.  Rather, I can set
(most) preferences, but they're not saved.  This message shows up in
the error console.

Error: uncaught exception: [Exception... "Component returned failure
code: 0x80520015 (NS_ERROR_FILE_ACCESS_DENIED)
[nsIPrefService.savePrefFile]"  nsresult: "0x80520015
(NS_ERROR_FILE_ACCESS_DENIED)"  location: "JS frame ::
chrome://global/content/bindings/preferences.xml ::
set_valueFromPreferences :: line 334"  data: no]

I can't even set http proxies; I set a similar message, except pointing
to line 1062.  

I'm assuming that this has something to do with the pkgsrc/NetBSD
port.  I'm running sunbird-0.3.1, from HEAD, on -current.  (I noticed
that sunbird has a very large number of patches.)  Any suggestions?

                --Steve Bellovin, http://www.cs.columbia.edu/~smb