I downloaded and used the Tile Merger [spoiler](http://rmrk.net/index.php/topic,35097.0.html)[/spoiler]
The problem is that it does nothing, I extracted the project, put the tilesets I wanted to merge in the appropriate folder and then ran the game, The screen is black and does nothing, it then produces two .rar files, both of which are 0KB (hoge.rar and temp.rar) It does not produce a merged tileset.
*edit* the 'hoge' file size changes after the game has been shutdown. This might mean that it's working, i'll leave the project running for a while.
*edit* I have fixed the problem