Still got a constraint problem...

Hi! I’m doing a animation of a large crane for my employer, but I’ve come across a problem I can’t seem to figure out. I’m trying to get the hydraulic cylinders constrained so that they animate properly. To do this I am using “TRACK TO”. I select the bottom half of the cylinder, and the pivot point of the upper cylinder, and apply the constraint. No prob, works perfectly. The problem is that when I try to do the same thing with the upper cylinder, it doesn’t work. Instead, the “const” box turns red, indicating a problem. I can orient it in any direction and it will work, except in the direction I need it to be in (which is Y). I don’t understand? Any ideas?

You sure that Y isn’t accidently also the axis that is set to point up in the track to contraint???
If you look at the Track-To dialogue, there is a set of buttons following “To:” and a set following “Up:”. These can’t be the same.