I've flashed a new ROM and restored the app from Google Play.
Among them, Titanium Backup and it's Pro key.
First I've saw the error "not enough free storage".
Then uninstalled both the app and the key. Reinstalled.
Wipe dalvik cache and cache...
Nothing works more.
I can install but it always shown Version Pro (donation) - Thank you! but I cannot backup anything.
P.S. I do not have an .odex file in system\data folder (as suggested in other threads).
What can I do?