The Witcher was first released in 2007. A few things changed since then. Hence two of the options in The Witcher launcher are obsolete:
1. “Register game” is obsolete
There is no need and no way to register our games on our website. You can however create an account on http://forums.cdprojektred.com/ to participate in the life of The Witcher community.
2. “Check for updates” is obsolete
The Witcher updates are available here. Please note that 1.6.2 fixes Mac-specific issues (Wine-related) and is for Mac only.
The digital Enhanced Edition for the PC usually does not need to be updated. Some older versions of the Enhanced Edition and versions of The Witcher older than Enhanced Edition need to be updated with patch 1.4 and language packs to not require registration (which as we mentioned does not work anymore) to run.
As patching with the 1.4 patch may take a long time it may be preferrable to simply claim the digital backup copy of the game on gog.com. This version of the game is fully updated from the start. Find the instructions on how to claim it here.