imagettftext() question

I've written a script that displays a graph of some data from a text file. Beneath each bar in the graph is a text label. I read the php.net documentation and it seemed that imagettftext() was the easiest function to get text in an image with, so I used that. Here is the text-display code (syntax is all correct): imagettftext($im, 10, 0, $i * 100 + 10, 190, $black, "arial", str_pad($candidates[$i][0], 12, " ", STR_PAD_BOTH)); This code works perfectly well on both windows machines I've tried it on, but causes an error in the image on both non-windows (Unix variants) machines I've tried it on. Does anyone have -any idea why its breaking? -a solution to get it to work on *nix machines? -a different way to display text in an image? Thanks a lot.