Whatever you do regarding UP, do not do it on/with that 4.10.1m installation of yours!
To get UltraPack 2.01 running, you will need to start with a fresh 4.09m installation.
1.First you create a backup copy of 4.10.1m. Copy the whole folder to a different folder. Name that new folder 'Backup1946-4.10.1m'.
2. Next you need to install 1946 and patch it up to 4.09m, in a seperate folder. Name the folder '1946UP2.01' or similar, so it's easy to recognize.
Installing it from DVD might result into you loosing 4.10.1m, as it will probably want to un-install it. That's why you've created that backup of 4.10.1m folder!
(You could try and prevent that un-install from being really succesfull, by renaming the original 'IL-2 Sturmovik 1946' folder to something else, like '1946 4.10.1m', before you run the install from DVD)
3. After 1946 has installed from DVD, copy the file conf.ini and the folder 'users' from the backup copy folder ('Backup1946-4.10.1m) to the new installation. (in folder '1946UP2.01')
See if it will start. If it does, patch it up to 4.08m and 4.09m.
4. Create a backup copy of that 4.09m installation, before you take the next step.
5. Then do as Toad suggests in this topic
(Unzip that UpUpdater stuff to the 1946UP2.01 folder, run it from there.)
6. After that has completed, you will need to create some new shortcuts to start the game... (Right click the file IL2fb.exe in each game-folder, choose Send To, Desktop (create shortcut).
Rename each shortcut (select icon, press F2) to the version it's pointing to... Also create a shortcut to 1946UP2.01\jsgme.exe.
Thats basically the "easiest" way to do it, though you can speed the process up considerably by skipping the 'create backup' items, but I would advise against doing so.
But, wait for others' suggestions, I just woke up....