Going to those coordinates causes no problems for me other than that they seemed to be in- or underground? Standing top side I see this:
Falling through the floor is often a symptom of not having a very good connection to the server. To verify this please go to
http://www.speedtest.net/ and select Amsterdam as a server and then run a test.
For TFC to work ideal you'll need 1mbit of upload and 5mbit of download with a latency below 100ms. If you don't reach these numbers that doesn't mean you can't play TFC on our server, just that the connection is less than ideal. Having less upload can cause the client to get disconnected. Not having enough download can cause chunks to load very slowly or not at all, especially after joining or teleporting to another location. Having higher latency can cause rubber banding effect or block lag.
The people who log of right after logging on is often caused by the mod control we're running on the server. This kicks clients that have mods installed which we haven't whitelisted on our server.
That all being said. It could also be a problem with my Internet connection. Although at the moment I see no evidence of that. Here's the current latency graph for the past 8 hours. It shows a latency of just over 3ms to my Internet gateway which is located at a data center at the Amsterdam Internet Exchange.