Hi,
Think I posted this in the wrong place originally (https://forums.zotero.org/discussion/39892/word-plugin-fails-to-respond-after-installing-a-new-citation-style/#Comment_203559)

I had the same problem discussed in that thread today ie "zotero experienced an error updating your document. Database permanently closed; not re-opening".

I haven't installed a new style or made any other changes since yesterday, when it worked fine. I changed back to the old plug in as in the posts in the other thread, and that seems to make the tool bar respond. But having done that, I now can't open Zotero - when I click on the Z, I get:

"XML Parsing Error: undefined entity
Location: chrome://zotero/content/tab.xul
Line Number 34, Column 3:
<menuitem id="context-undo"
----------------^"

I'm on the latest version of Firefox (33.0) and set for Zotero automatic updates - it's showing version 4.0.20. I've tried restarting everything.

Final weeks of thesis writing...so would really appreciate some advice!
Thanks