Have also tried to enter the serial number, without luck, requested a manual unlock key yesterday from
support@telltalegames.com, but they say it might take a couple of days before they respond, so I will wait patiently.
The debug version of the dll, is probably because I installed a DirectX SDK kit, as suggested somewhere else in this forum, no luck though, I will revert back to the retail version, and let you know if there is any changes.
I will do a new download/install (and delete the temp directory) after uninstall of SDK directX, (just for fun
)