firefox not using plugins on all websites

despite about:plugins listing the appropriate plugins, there are 2 websites that can't see them (both work fine in chrome):

1) conferencing.level3.com uses a java plugin to run web conferences, but claims "java is not installed"

other websites are able to use java, and about:plugins shows:
IcedTea-Web Plugin (using IcedTea-Web 1.4.2 (1.4.2-1ubuntu2))

    File: IcedTeaPlugin.so
    Path: /usr/lib/jvm/java-7-openjdk-amd64/jre/lib/amd64/IcedTeaPlugin.so
    Version:
    State: Enabled
    The IcedTea-Web Plugin executes Java applets.

MIME Type Description Suffixes
application/x-java-vm IcedTea class,jar
application/x-java-applet IcedTea class,jar
application/x-java-applet;version=1.1 IcedTea class,jar
application/x-java-applet;version=1.1.1 IcedTea class,jar
application/x-java-applet;version=1.1.2 IcedTea class,jar
application/x-java-applet;version=1.1.3 IcedTea class,jar
application/x-java-applet;version=1.2 IcedTea class,jar
application/x-java-applet;version=1.2.1 IcedTea class,jar
application/x-java-applet;version=1.2.2 IcedTea class,jar
application/x-java-applet;version=1.3 IcedTea class,jar
application/x-java-applet;version=1.3.1 IcedTea class,jar
application/x-java-applet;version=1.4 IcedTea class,jar
application/x-java-applet;version=1.4.1 IcedTea class,jar
application/x-java-applet;version=1.4.2 IcedTea class,jar
application/x-java-applet;version=1.5 IcedTea class,jar
application/x-java-applet;version=1.6 IcedTea class,jar
application/x-java-applet;version=1.7 IcedTea class,jar
application/x-java-applet;jpi-version=1.7.0_50 IcedTea class,jar
application/x-java-bean IcedTea class,jar
application/x-java-bean;version=1.1 IcedTea class,jar
application/x-java-bean;version=1.1.1 IcedTea class,jar
application/x-java-bean;version=1.1.2 IcedTea class,jar
application/x-java-bean;version=1.1.3 IcedTea class,jar
application/x-java-bean;version=1.2 IcedTea class,jar
application/x-java-bean;version=1.2.1 IcedTea class,jar
application/x-java-bean;version=1.2.2 IcedTea class,jar
application/x-java-bean;version=1.3 IcedTea class,jar
application/x-java-bean;version=1.3.1 IcedTea class,jar
application/x-java-bean;version=1.4 IcedTea class,jar
application/x-java-bean;version=1.4.1 IcedTea class,jar
application/x-java-bean;version=1.4.2 IcedTea class,jar
application/x-java-bean;version=1.5 IcedTea class,jar
application/x-java-bean;version=1.6 IcedTea class,jar
application/x-java-bean;version=1.7 IcedTea class,jar
application/x-java-bean;jpi-version=1.7.0_50 IcedTea class,jar
application/x-java-vm-npruntime IcedTea

2) bluejeans.com video conferences claim their plugin is not installed, even though about:plugins shows:
bjninstallplugin

    File: npbjninstallplugin_2.4.143.8.so
    Path: /usr/lib/mozilla/plugins/npbjninstallplugin_2.4.143.8.so
    Version: 2.4.143.8
    State: Enabled

MIME Type Description Suffixes
application/x-bjninstallplugin,version=2.4.143.8 Blue Jeans Installation Plugin
bjnplugin

    File: npbjnplugin_2.4.143.8.so
    Path: /usr/lib/mozilla/plugins/npbjnplugin_2.4.143.8.so
    Version: 2.4.143.8
    State: Enabled

MIME Type Description Suffixes
application/x-bjnplugin,version=2.4.143.8 Blue Jeans Video Plugin
application/x-bjnpluginslave,version=2.4.143.8 Blue Jeans Video Support Plugin
application/x-bjnloguploader,version=2.4.143.8 Blue Jeans Diagnostic Plugin

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: firefox 28.0~b2+build1-0ubuntu2
ProcVersionSignature: Ubuntu 3.13.0-16.36-generic 3.13.5
Uname: Linux 3.13.0-16-generic x86_64
NonfreeKernelModules: nvidia wl
AddonCompatCheckDisabled: False
ApportVersion: 2.13.3-0ubuntu1
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC1: jbarnett 2543 F.... pulseaudio
 /dev/snd/controlC0: jbarnett 2543 F.... pulseaudio
BuildID: 20140226081007
Channel: Unavailable
CurrentDesktop: GNOME
Date: Wed Mar 12 13:26:05 2014
Extensions: extensions.sqlite corrupt or missing
ForcedLayersAccel: False
IfupdownConfig:
 # interfaces(5) file used by ifup(8) and ifdown(8)
 auto lo
 iface lo inet loopback
IncompatibleExtensions: Unavailable (corrupt or non-existant compatibility.ini or extensions.sqlite)
InstallationDate: Installed on 2014-02-24 (16 days ago)
InstallationMedia: Ubuntu-GNOME 14.04 "Trusty Tahr" - Alpha amd64 (20140218)
Locales: extensions.sqlite corrupt or missing
PrefSources:
 prefs.js
 /usr/share/mozilla/extensions/{ec8030f7-c20a-464f-9b0e-13a3a9e97384}/<email address hidden>/defaults/preferences/001ubuntu-gnome-mods.js
ProcEnviron:
 TERM=xterm
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
Profiles: Profile0 (Default) - LastVersion=28.0/20140226081007 (In use)
RelatedPackageVersions:
 rhythmbox-mozilla 3.0.1-1ubuntu12
 icedtea-7-plugin 1.4.2-1ubuntu2
 bjnplugin 2.4.143.8-1
 gnome-shell 3.11.90-0ubuntu1~trusty1
 google-talkplugin 5.1.5.0-1
RunningIncompatibleAddons: False
SourcePackage: firefox
Themes: extensions.sqlite corrupt or missing
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 10/18/2013
dmi.bios.vendor: Apple Inc.
dmi.bios.version: MBP112.88Z.0138.B02.1310181745
dmi.board.asset.tag: Base Board Asset Tag#
dmi.board.name: Mac-2BD1B31983FE1663
dmi.board.vendor: Apple Inc.
dmi.board.version: MacBookPro11,3
dmi.chassis.type: 10
dmi.chassis.vendor: Apple Inc.
dmi.chassis.version: Mac-2BD1B31983FE1663
dmi.modalias: dmi:bvnAppleInc.:bvrMBP112.88Z.0138.B02.1310181745:bd10/18/2013:svnAppleInc.:pnMacBookPro11,3:pvr1.0:rvnAppleInc.:rnMac-2BD1B31983FE1663:rvrMacBookPro11,3:cvnAppleInc.:ct10:cvrMac-2BD1B31983FE1663:
dmi.product.name: MacBookPro11,3
dmi.product.version: 1.0
dmi.sys.vendor: Apple Inc.