hi Peter.
Perhaps, you have never install the XOOPS yet.
First, you have to install the XOOPS.
After this, you can find the place to patch in mainfile.php created newly.
I am an idiot ... plain and simple. 3 times I looked at the mainfile.php and could not find the specific lines.
I checked again after your post ... I found them. I must be going blind in my old age
Oh ... and yes... I had XOOPs installed
Thanks for your patience
Peter