Licaon_Kter: You know where they're saved as the
browser asks you !!!!?
Actually, many browsers do not do this by default, you have to change settings before they will ask you where to save files. However, there is a default location that the browser will save files to (probably a "my downloads" or similar).
For the OP: as others have said, you want to avoid using the launcher to patch the game... if you are online, the launcher will automatically apply patch v1.3, which you don't want. So instead, you need to get the patches separately and then make sure you are OFFLINE when installing the game. Once it's installed, run the patches in order, v1.1 first, then v1.2.
Regarding the error you are getting with running patch v1.1, my guess is that the game did not fully uninstall. When you uninstall the game, after the process finishes, go look for the game folder. This will be wherever you chose to install it, but by default it's probably somewhere in Program Files, probably Program Files\CDProjekt\Withcer 2 or something like that. If the folder is still there, delete it. Then, go to your "My Documents" folder and look for a folder for the Witcher 2. Delete that as well. Now the game should be fully removed from your system.
Then, disconnect from the internet and install the game. When it's done, apply patch 1.1, then 1.2. When they're all done, you can reconnect to the internet. You may want to avoid using the game's launcher after this is done... instead find witcher2.exe in your install directory and run directly from that (or create a shortcut to it).
A question for those who have the boxed version: I heard that it originally shipped with some DRM that was patched out after about a week. Would this cause problems when trying to install the game offline? Is it patch v1.1 that removes the DRM from boxed copies?