Since you didn't include any of your symbols, I couldn't be sure why it's not working.
Splitting responsetext is prone to errors though, it's better to get the actual element.
Here's some code I created for someone else on here the other day:
Set references to Microsoft XML and Microsoft HTML
This gets the current stock price from google finance and works like a function.
So in a cell you could say "=Stockquote(aapl)" and it would get the stock quote for Apple.
I can easily adjust this to yahoo - just give me a link and specify what you'd like to get.