First off, I don't know if W8 users are having the same symptoms as W7 users, who found that installing the game directly to the desktop and not the EA Sports folder or anywhere else in the program files folder, solved their problem.
The other thing is, don't use TiT to install the rosters. Go directly to the database sub-folder, wipe those 19 .dat files, and unzip the file directly into there. TiT will only have it try to overwrite, which may not work.
I would try this second part, first, since it would the simplest course.
If that doesn't work, before you go about re-installing everything, simply try moving the folder to the desktop first.