DW ask "Are you performing an upgrade ?" on a new installation

Set up a new installation of 5.4M1 over any DB except Hsqldb, at startup the DW propose to setup the wiki. At step1, it ask if this is an upgrade because 33 documents are found in the DB. This is wrong, since this a new installation, and those 33 documents are mandatory documents automatically created a few milli seconds ago by the wiki itself.