The Witcher 2 howtos and workarounds

Windows version
You can import a saved game from The Witcher by selecting "New Game" then "Import Witcher 1 Save" from the main menu. In order to be used, the saved game files should be in their original location (most likely ) and have been created during the Ice Plains or Order of the Flaming Rose Cloister portions of the Epilogue. Also, make sure that at least one of six most recent saves is one from the main game mode and not any of the extra adventures. The Witcher 2 games seems to recognize only the last six game saves so if one finished the game and then made saves in the additional adventures the game won't detect any saved games from the original game. In order to fix this either load and re-save the most recent save made in the main game, as mentioned made during or after the Ice Plains or copy such a save file into The Witcher 2 save folder.

Importing Witcher 1 endgame saves
To import endgame saves from Witcher 1, create the following directory and place them in it:

$HOME/.local/share/cdprojektred/witcher2/GameDocuments/The Witcher/saves

This allows carrying over various items like armor and swords as well as plot choices from the first game which have an effect on the second.