As documented in this thread on the Processing forums the TileSaver class seems to be broken for current versions of Processing. Sadly I’m not sure what the problem is and I don’t have time to fix it right now.
However, I tried the original TileSaver code posted back in 2006 and miraculously that still works. This would imply a larger issue with the unlekkerLib library and Processing 1.0, which I’ll have to address when I have the time.
For now, here is a link to a working Processing sketch using the old TileSaver code: TileSaverTest.zip