Thanks,
in fact the -o options outputs the information to a file, but if -q quiet mode is activated at the same time, the file is empty. This look to do exactly the same as a file redirection (> wget.log). So I have to set -nv non-verbose option with the -o option and then seek the generated file for errors. I can live with that limitation but there surely are a variable set by wget (à la ERRORLEVEL) that can give me the error type/number right away, isnt-it?
yp