Hello,
Im having an issue with the auto rig in Houdini, when I hit the
create/modify/match rig button I'm getting the errors in the attachment
can anyone give me any advice on what I'm doing wrong?

im using houdini 15.5.523
on a mac os sierra
2.7 GHz 12-Core Intel Xeon E5
AMD FirePro D700 6144 MB

You probably haven't updated the parameters on your deform rig yet.

is there a page/ tutorial on how to adjust that?

It's basically the same thing you had to do for the animation parameters but do it on the deform rig itself.

The step I'm thinking about is “Set up the animation rig asset” > Step #5 from here:
http://www.sidefx.com/docs/houdini/character/biped [sidefx.com]

There's also the old tutorial on the autorig system: https://archive.sidefx.com/index.php?option=com_content&task=view&id=991&Itemid=258 [archive.sidefx.com]

Thankyou very much!!!