what you need to do first is run the uninstall sql to get rid of the tables in your database that it created...they are no good check admin to make sure the duplicates are gone and repeat for each one that remains til they are all gone.

then go to your database and make certain you have written the prefix to your tables correctly...


some start with:
zencart_
zen_
shoppe_
store_
zc_

see what is the first part of the table and that is what you need to write in front of the first few places in the sql before you try to install it.

make certain you have your files in the right spots too