Adding 4th axis to my gantry machine, getting "Following Error"

I've got a mostly-working 4-joing gantry machine that I just added a fourth axis to. It uses Teknic SDSK stepper motors on all five joints. I started by duplicating the entry for my z-axis, but I get "following error" whenever I try to jog it. Searching the forums turns up issues around some of the stepgen configuration, but I copied mine from my working Z-axis.

You can see the files here .

As I was making these modifications, I'd often get the alert popping up saying that this version of LinuxCNC needs a new INI file format. This generally occurred if I didn't have axes and joints matching properly, but also occurred when I didn't specify HOME_SEARCH_VEL (which is documented to default to 0). In any case, I'm not sure if I've properly configured all my axes and joints.

I also think I have a lot of redundant parameters specified, around MAX_ACCEL and MAX_VEL, stuff like that. I have them specified in both AXIS_x and JOINT_x. I'm not sure if I can remove some of these or not.

Any help is much appreciated.

I'm not sure I understand why f-error is not in the same units as everything else. The docs I read say the units are the same. In this case, it's an angular axis, so inches doesn't make sense.

Also, this image link is broken; it would be helpful to see it. wiki.linuxcnc.org/cgi-bin/wiki.pl?Following_Error