I had the same problem, which started yesterday. I'm specifically referring to the "LG IMS has stopped" message. I contacted Vodafone, but they directed me to a menu in the phone that didn't exist. I took a punt, and tried Settings, Backup And Reset, Network Settings Reset. Note: this is not a full reset, and you don't lose apps, etc. You will have to sign back into your wifi, as the phone "forgets" the wifi setting. Once you have signed back in, the problem is gone.