Problem with megamenu changes not applied.

Hi there, I am new to this and have a problem.(Joomla 2.5.14 - VM 2.0.24 - T3 Framework).
I started experimenting with T3 - built a Megamenu and out of the blue it stopped working.
I uninstalled T3 & JA extensions and reinstalled only T3 Package.
I customized t3 template re created the megamenu but still not working.
It seems that though it says "Saved succesfully" it doesn't save the change.

Any ideas?
Thanks in advance