1. In Disk: Copy the entire contents of the disk to disk.
2. Download the latest Anno 1404 Venice Patch (Stand 2015, patch 2.1).
3. The patch rename anno1404_Patch_1.2.exe
4. Locate and open the add-on folder after folder patch_1.2.
5. Delete the patch file in said folder, and replace it with the downloaded and renamed Patch.
The installation should now work smoothly. Importantly, 2.1 to install after the installtion the patch again!