I just sent an e-mail via your contact us section, but am following up here. I am having the same problem related here, but I am running the latest versions (non-beta) of both FF4 and 1P (3.5.9)
I have my diagnostic report I can send (please provide e-mail).
I looked for this file:
Also in the email, please take a screenshot of the Firefox 4 folder: ‘<Your Home Folder>/Library/Application Support/1Password/Extensions/30868/[email protected]
but the 30868 folder does not exist, rather there is a 30884 folder that does contain stuff (screenshot attached)