I've sent in error report '1713666275'

When I click any button on the Zotero toolbar in Word, I get 'Word could not communicate with Zotero. Please check firefox is running and try again'.

Firefox is running. I have tried restarting both word and firefox.
The problem occurs with both new and existing docs

I am running :
Zotero 2.0rc5
Word plugin 3.0a
Firefox 3.5.6
XP (Version 5.1.2600 Service Pack 3 Build 2600) and
Word 2003 (11.0.8313)

I upgraded to 2.0rc5 a few days ago, and that seems fine.
I upgraded the word plugin this morning (first time since upgrading to Zotero 2.0), and it hasn't worked since.

Any help gratefully received!

Thanks

Cathryn