I am having this problem with my contacts also. I moved the yahoo files into the sytem/app. They are all there. I rebooted my phone and it did not fix the problem. I don't understand what people are talking when they say you have to change permissions or ownership. I tried to install the files and they all come up with a message saying "application not installed." Can someone please explain what I need to do next?
Edit: I think I figured out the permissions thing. All of the missing files are now set to
User: r,w,x
Group: r,w,x
Other: r,w,x
User: root
Group: root
Is this correct? It still does not work after this. Am I missing something?