ok, the strategy for this will be a little diferant then the download center tutorial, and it will require that you are familiar with the concept of nested recordsets.
the basic outline of how to accomlish this is:
1) you need a table that contains the names of the files to download:
downloadID - Primary Key
downloadFileName - the name of the file to download
2) you will need a table to record the downloads by the user:
userdownloadID - Prioary Key
userdownloadUserID - releates to the users.UserID column
userdownloadsDownloadID - relates to the downloads.downloadID
3) on the download page, create a recordset to query the downloads table and return the files that are available for download.
add a form with a submit button, a hidden element that is bound to the downloadFileName column, another hidden element that is bound to the downloadID column
add a repeat region around the form so that the form repeats for each available file name.
4) heres where the nested recordset comes into play. Inside the repeat region, you need a recordset to query the userdownloads table. filter the userdownloadUserID column using the session for the logged in user, and filter the userdownloadsDownloadID column on the downloadID column from the main recordset.
for more details on the nested recordset concept see the following tutorial:
use a Show region behavior around the download form so that it only shows if the nested recordset is empty.
5) Add the download file behavior, for the file name, use the downloadFileName hidden element
6) add a insert record server behavior to record the file download.
it will insert to the userdownloads table. for the userdownloadUserID column use the User ID session variable. for the userdownloadsDownloadID column use the downloadID form element.
the concept behind this is to record each time a download happens, storing the ID for the downloaded file and the ID for the user.
this information is used to determine whether the download form for that file should show or not based on the user that is logged in.