Just guessing here, but did you copy/paste the whole save folder from 2.61 or did you open the save folder in 2.61 and copy the save files into the 2.71 save folder?
The later is known to create problems..
Have mentioned this before, but will mention it again: To be sure to not have any problems:
1: Download full version, not Lite but full.
2: Open your 2.61 www folder and copy the "save" folder, do not open it, copy the folder un-opened
3: Paste that save folder from 2.61 into the 2.71 www folder, overwrite if needed.
4: download, or copy from older download, the Incest Patch, place that into the www folder as well.
5: Do NOT use the cheat mod, if you do want to do that, at least wait till the mod is 2.71 and not 2.70
Now the game should work as intended, unless your old saves have been corrupted from prior wrong use of cheats or whatever, in that case test if any save work.. if they don't.. well then start over clean.
Fiddling around with files too much, without knowing what ya doing, makes it very possible to break something in games like these.