For those who have a problem with no vibration on dialer or incoming call,please checks your installed applications such as theme,launcher or anything app that using more memory or ram..i have the same problem but now everything works perfectly.i realised that after i've installed a adw ex theme then the problem begins to appear..then i removed or uninstall the theme and its working again..forgive me if this solution did'nt work for others,i just want to share my experience regarding this problem.