Wireless extreme good on iMac not on MacBook Pro

I've been listening to sound on my MacBook Pro in via wireless networking in the house from Airport Extreme which is hooked upstairs into my iMac and then is sent to my Airport Express in the kitchen connected to speakers. I've had no problems sending sound through Airfoil software from my laptop to the kitchen speakers or from my iMac to the kitchen speakers. Suddenly, when I send from laptop, it connects and the sounds stops on the laptop but doesn't make it to the kitchen speakers. Yet, it is still working fine when I send sytem sound to the same speakers through the same wireless set up from my iMac. So, I'm thinking this has something to do with my laptop. The volume buttons have already been checked including sound in the preferences menu. Any ideas?