Here we go again: for those still experiencing issues with Wi-Fi we have a new test firmware that consists in a major upgrade for your evaluation:
http://update.archos.com/9/gen9/gen9...archos_it4.aos
Please note that this firmware also includes i) skype audio fix, ii) SGX performance boost, iii) some more CPU scheduler stability patches.
If this is not the ultimate solution, it would be great to generate logs of the failures by installing/running the following applications after witnessing a problem:
http://update.archos.com/9/gen9/debug/LogExtractor.apk
that will generate a zip of the logs at the root of your tablet and post the result.

Thank you for your help and patience.