This question is basically a continuation of this previous question. Never mind, here's the deal:
I've made a LAN cable that goes through a wall, but it doesn't work. The cable is roughly 10m/30ft long. I crimped both ends myself according to this detailed explanation, and the job looks to be well done; all the wires are all the way in the plug.
I bought a cable tester after not being able to fix this. I thought perhaps the cable has a bad kink somewhere. But the cable tester says all wires are okay! The cable tester flashes its lights nicely in the correct sequence. According to the half-chinese instruction page, this indicates that everything is wired correctly. Even if I might have the wrong color sequence, the copper itself seems to be correct.
But when I unplug the LAN cable sneaking through the hallways, and connect this new LAN cable instead, Windows reports that there's no network.
What can be wrong? How can I find out?
Updated: Italic text above, in response to the first few answers.