Thanks for the feedback. I live in Perth, Western Australia. I have been using Firefox 4 since it was released. 18 April was the first time I used the CHDK search engine with FF4.0.
Sometimes it pays to report the issue in case other users experience the same problem.
You are probably correct in your observation. My understanding is that the English CHDK Forum is hosted in the USA. Since the Japan earthquake, the Australian internet has at times been erratic. Maybe the issue is just caused by the local internet traffic congestion.