Hi guys,
The ''not enough phone memory'' error usually happens when one of the files found on mobile phone is corrupted which even after resetting to factory default settings does not get solved or solves the issue which will keep on displaying this error.
Only solution for it will be flashing the mobile phone and software platform reinstalled completely by which ill advise to copy all contacts to sim or backup on memory card as all will be deleted during this process.There is another way which does not usually work is to press on holding menu key and end the running applications in background ,this works on old models of mobile phones such as Nokia 6600,n&0 etc....
Recently i tried this another one for my Nokia 6500-s,i installed Nokia updater on my laptop,connect mobile to laptop when only it was prompted ,removing memory card and set profile to general then it reinstalled the same version i had since there is no new version,Now im using my mobile phone correctly .You can give a try but i do not guarantee anything except leaving it to a mobile phone repair center and let them do the flashing.
Good luck