Firefox broke after flash

[Koua Lo]

I tried installing the flash plugin for Firefox via the plguin manager.
After installing, this is the error message I got:

selected locale: en-US
INTERNAL ERROR on Browser End: Could not get the plugin manager
System error?:: Success

Firefox no longer works.  I uninstalled it, and re-installed it via
Synaptics but the same error message comes up everytime I tried to
launch Firefox.