what can couse collision and partition on a hub?

I've got a problem with connection through a hub. When I plug my laptop to the hub with a cable (category 5 patch cord - says on the cable), the led named "Collision" flashes constantly. When other computers are connected to this hub, the port goes offline with "partition" led flashing (obviously due to collisiont problem). Even when only the problematic computer is connected and the hub is not connected to the outside world, there is a collision - so I guess it's something with the computer or the cable. There should not be any double ip's on that network (but even so - when only one computer is connected - it shouldn't matter).
When the laptop is disconnected, other computers work fine.
On the other hand, when I connect laptop directly to the socket in the wall (the same socket the hub should uplink), I can connect (as you see, I can write this question from the laptop).
What can be the problem? The hub is an old one, so it may not be able to recognice cross'ed over cables. But I tried some other cable, that worked on other computer connected to that hub with the same result.
Please help.