hey!
i just installed mine on my laptop (vista) and got almost no problem at all with saving, so sorry can't help you with that problem ._.
so i thought i just tell how i installed the game:
1. burned the iso to a cd, and run it...
2. got problems at installing, cause it wouldn't make the omerta folder, so i found this post ->
here
opened the disc and opened the omerta folder and right clicked on setup and clicked run as administrator!
3. installed the games without any problems
4. put the extracted zip-patch alsignup_??? to the folder where omerta is installed to (there's also omerta_m)
5. then start the game double clicking omerta_m
reminder:
quicksave is not the same as saving! quicksave is a quicksave, like when quicksave before responding and then you can just quickload to go back! when you wanna save, you have to right-click, a menu? opens and there you save, where you also have to name the saving.
also there is no save-data file in the omerta folder! i checked it.. and i saved and can load.
so, if you did all that, and it still didn't help, i don't know, sorry