"Recaptcha is not defined" javascript error in Firefox

[cyberhobo]

I'm using the WP-reCAPTCHA WordPress plugin on a development site. The
registration page loads the reCAPTCHA interface fine in all browsers
but Firefox, which just displays a blank page. With FF 3.5.1 and
FireBug 1.4.1, the console output is:

Recaptcha is not defined
anonymous() recaptcha.js (Line 451)
anonymous() recaptcha.js (Line 223)

My client would rather I not publish the development URL, but if
anyone would like to see the problem I'll share it individually.

Thanks for any help.

[cyberhobo]

I was able to find a jQuery script in the header of page that seems to
cause the problem, though I haven't figured out exactly what the
conflict is or why the error shows up in recaptcha.js. When I remove
that script reCAPTCHA works in Firefox again.