Ok, after reading from gcampton i succeeded with a softer approach, i.e. I changed the value of the parameter “~away mode” (don’t remember the exact name) in the general options table, and it worked…
… coming back to admin page, I realized I was at the source of the error, having defined my “away time slot” incorrectly.
Thanks
PS spaciouscritter, you must enable “show hidden files” in your FTP client in order to see the .htaccess file.
I recommend trying my softer approach : you will easily find the field in the WordPress options table, then change the string “enabled” into “disabled”