Comment 2 for bug 551811

I get the following error trying to save the settings in the preferences dialog:

Hook prefsSaveHook failed: 1
can't read "tmpCertPrefs(usecertfile)": no such variable
    while executing
"set jprefs(tls,$key) $tmpCertPrefs($key)"
    (procedure "ServersSaveHook" line 10)
    invoked from within
"ServersSaveHook"
    (procedure "::PrefNet::SavePrefsHook" line 3)
    invoked from within
"::PrefNet::SavePrefsHook"
    ("eval" body line 1)
    invoked from within
"eval $func $args"
can't read "tmpCertPrefs(usecertfile)": no such variable
    while executing
"set jprefs(tls,$key) $tmpCertPrefs($key)"
    (procedure "ServersSaveHook" line 10)
    invoked from within
"ServersSaveHook"
    (procedure "::PrefNet::SavePrefsHook" line 3)
    invoked from within
"::PrefNet::SavePrefsHook"
    ("eval" body line 1)
    invoked from within
"eval $func $args"

Also, what is the difference between the three certificate options? This is not 100% clear to me.