> I'm trying to use BFAV2 for the first time with an 3.7a-5707 
> image and the ChronologyClasses fix without success. When i 
> launch the BFAV browser, i got the following error : 
> HTTP response is nil, unable to proceed.

Serge - what platform are you on?  

If you are on Windows, you must make sure that you are using the current
(3.6.2) Windows VM.  3.6.1 and earlier Windows VMs produce the bug you
reported.