Streaming video and router

Hi, just bought and installed a Linksys WRK54G router with a wired main PC,
also a WPC54G card for my laptop.
Everything seems to work just fine except that when I try to play streaming
video through either the wireless laptop, or the wired PC, the router seems
to lock up. I can only get the connections back by re-booting the router. I
have the current firmware installed, checked the MTU settings by pinging
sites. Anyone have any ideas?

Cheers, Dave P