Geektool: cat command doesn't work

I'm trying to get Geektool to display a txt file, but the Geeklet stays blank.

It displays just fine when I enter:

date
date +%d

But when I enter the following it does not display:

cat ~/Desktop/todo.txt

I've copy pasted the text into terminal and it retus the text just fine.

I'm using v3.0.1 and OSX 10.6.8