I just bought a Toshiba Satellite M100 laptop. It is running Vista Home Premium and everything seems fine except when I capture video from my DV, it keeps dropping the connection (IEEE 1394). I need to unplug the FireWire cable and reconnect it again to get back the connection. But later it dropped again. This never happened with my old laptop. I used the same program (Adobe Premier pro 1.5), the same DV and the same FireWire cable.
Any ideas?

It can be a hardware related problem, but check the BIOS version installed on your laptop first. After that visit the manufacturer’s website, find out if there is a more recent version of the BIOS available for downloads and if the new release covers your issue. Update the BIOS if needed and see if it helps. I’ve seen it many times before when the BIOS update fixes very strange laptop issues.

Could it be a hardware problem? say, loose cable of the FireWire socket?

The FireWire socket is soldered directly to the motherboard, there cannot be loose cable. If the socket itself is bad then it’s necessary to remove the motherboard and replace the firwire port. Probably your laptop is still covered by warranty and Toshiba (or authorized center) will replace the motherboard at no charge.
If you don’t want to replace the motherboard on have no time for it, you can go with a FireWire PCMCIA adapter, you plug it into the available PC slot on your laptop and get a few FireWire ports.