First, I REALLY appreciate the fast response. 
Okay, other than "License Agreement" I see on the "Add File" page, I don't see any "license codes link".
After I attach file, the page only reloads to show a fresh "Add Picture" & "Add file page". Nothing new comes up.
And also, I have tested it with the help of Paypal Sand Box; when I accessed what was suppose to be the code delivery email, this was all I saw;
I clicked on the link, it took me to a page that has a blank form about adding licenses, when I type in the codes and click "Add License", the following database error is displayed:
Database Error
You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '0,'lopt')' at line 4
File: /misc/38/000/138/981/6/user/web/gamemasterz.org/forum/Sources/Store2.php
Line: 3455
Note: It appears that your database may require an upgrade. Your forum's files are currently at version SMF 2.0 RC1-1, while your database is at version 2.0RC1-1. The above error might possibly go away if you execute the latest version of upgrade.php.
EDIT:
lopt was the code/license I tried adding before the error came up.
I need help with these. Something is definitely wrong somewhere.
Thanks.