Hmm... never seen this message, but I think it might refer to Canon settings, try reading page 67 in your Canon Advanced User Guide (on CD only, at least in my package for i70/SD1000).
Mind, this has no 'blank browse' setting, but it might be a good idea to set it to 'Not Assigned' (default setting) to avoid interference with CHDK's use of the <Alt> button.
hope this helps,
wim