I dont know why there are three configure.php.
But it must be exsits when somebody get the problems as desribled above.
Go and check if there is a folder called " local" exsit under:
yourzencart/admin/includes/
and there is the another configure.php.
i know there is no such file in the default zencart files!
It may automatically come out during the copy process.
I mean i copy the all the zencart files from another exsited store.



