On your Sony TRV240, switch the camera into VCR mode, hit the menu button. In the VCR menu, with the "V" in the menu, scroll down to the A/V->DV OUT item, and make sure "on" is selected. Then go back to main menu, go down to the SETUP MENU, and ensure that USB Stream is "off".
Hope this helps. This is the settings I use when hooking up to my iBook Firewire.