Patryck,
Be sure the JVC DVHS drivers are enabled. I had this problem initially with a BR 50 as well, but once I'd gone into the system/hardware/drivers, it sprang to life.
Control Panel
System
Device Manager
AVC subunit
update driver
Don't search, I'll find the installation
Sound Video Game Controllers
JVC
I'm doing this by memory, I'm at a laptop with no camera/deck attached. Somewhere in this forum, perhaps a year or so ago, I posted specifics from when I was sitting with it.
I'm assuming you're using SP1, as SP2 should pick it straight up.
i'd assume (maybe wrongfully) that Patryk is using the HDV capture tool, not DV. XP without SP2 won't recognize HDV devices without going in and telling it to.