laptop firewire problem

hi

brought a laptop and a edirol sound fa 101 card to use via firewire.

the problem i have is when i use the sound card in a higher sample rate than 48hz the card cuts out every few seconds through the six pin pcmcia card , but is ok with the 4 pin built in firewire slot , trouble is i get a little background hum with the 4 pin slot ,

would you say a better quality firewire pcmcia card would help , can any1 recommend one , also the bus power doesnt work ethier through the laptop is that how it is with laptops.

can any1 help :4-dontkno