capturing audio

I have a ADVC-300 box and a Macbook pro that is about 2 weeks old. Im trying to convert some cassette tapes to CDs using my laptop. I cant get FCP studio 5 to record the audio. Im using a SOny tape deck with RCA plugs connected to the out of the tape deck going into the INput RCA jacks on the front of the ADVC300 unit. I have a 9 pin firewire going out of the back of the advc300 box going into the firewire 800 slot in the macbook book pro. I hooked up the video port to a cam corder because i was told i needed to have the video jack activated or something like that. I even used a 9 pin to 4 pin cable from the ADVc300 to the macbook pro and still no luck. I changed the input on the soundcard settings on the mac to line input from the MIc setting. I have bootcamp installed on my computer and also have adobe premiere and adobe audition 2.0 on the windows side. ive tried all three with little luck. What am i doing wrong or is there something else I need to buy?