I am also having the same problem.
I believe it is due to some software i installed.
The newer ones i installed are usbcontrol, pypianobar, Qlandkarte M,
Mstardict, Qstardict.
Do you have any of above installed ?

For me the problem is it previously gave error for device memory full and now after few days it gives error if i try to access any device memory like images/ video, also it gives error when i go in application manager. So i cannot uninstall any thing.. Also it does not allow changes in contacts or calender or any of default installed softwares
If anyone has a clue, please help !!