Bukkit

Please, keep in mind that you are only allowed to travel from a destination to another one. You cannot go to a destination if you are not on an existing one (except if you are an admin using the /tg {dest} command with the option -f). The sign teleportation also works by standing on an existing destination !

Concerning the teleportation blocks, it must be adjacents to an existing destination, and the destination block must be a teleportation block.

See this illustration:

The destination is on the "D" green block. Other green blocks are not on a destination, but in the game, they were all of the same kind of block, for instance, lime wool.

On the "O" block, where the greens blocks are placed in a "rectangular" form, or in line, you can travel as you were standing on the "D" destination block. Other locations are wrong. Other green blocks with the "X" are not valid because they do not form a "rectangular" surface containing the destination.

For portals, it is about the same. The destination has to be created on the green blocks, on the beneath picture, or on the "P" blocks, which represtent the portal blocks of the Nether portal. "F" blocks are for the "frame" of the portal.

If you don't place the destination on these blocks, your Nether portal will work as usual, even if you have well configured the TravelGates sign.

Remember that in the default configuration file, the Nether portal teleportation is disabled !