A network tester is a must if you're doing this stuff on a regular basis.

My guess for your problem is the network panel/outlet you're using. They come pre-wired in a number of configurations - that aren't exactly marked in a straight forward manner either.

I had all sorts of headaches when helping a friend wire up a few new panels in his house. We were going crazy trying to figure out what the problem was. The new jacks weren't wired the same as the older ones. Older jacks required crossing the tx/rx and the new ones required just a straight connection. Take a closer look at the pcb.

Bruno