At the risk of sounding like a cop-out, I honestly would advise ditching Y! Messenger and going with an all-in-one messenger such as Pigdin (formally GAIM), which is what I've been using for at least a couple of years now. Three reasons:
1) Very unlikely Pigdin will give you the same install errors as Y! Messenger.
2) Pigdin is a smaller, smoother running client that Y!, not so heavy on the images and unnecessary features.
3) If you use more than one messenger, it eats up less memory to run one all-in-one messenger instead of three separate ones.