Unknown error (invalid-request)

hi,

I’m using BW reCAPTCHA on my site with akismet
Since few days, i have the following error when i want to enter a comment on my post:
Unknown error (invalid-request). Please contact an administrator for more info

I checked where it can come from by disabling the plugins. the problem is clearly related to BW ReCaptcha.

What’s strange, i have the same site on my development environnement (wamp) where I can test previously to modify my production site. On the dev envt it works juste fine !!
I checked my google account, it’s ok

Any idea??

Thanks