Anthony,
Try compiling the following method in any class:
foo 1 = 1 ifTrue: [2]
I get the error 'positive if jumps only'.
Now, don't ask *why* someone would write such a method (anything you do to make it useful gets rid of the error) but this is a minimal example of an actual method in Comanche that has the same problem, so I thought I'd point it out.
Avi