[Xymon] internal server error after upgrade

[D.Forsyth at ru.ac.za]

Hi all
I'm running FreeBSD 7.4 and used 'portupgrade' to upgrade xymon-server  
and client today, to 4.3.10

Now, I cannot see any graphs.
showgraph.cgi and showgraph.sh never get built and installed.

When I click on a graph link I get '500 Internal server error'.
Very annoying is that none of the log files is particularly helpful  
about this!

Excerpt from http-error.log
[Thu Aug 09 19:55:02 2012] [error] [client 41.145.0.228] .: Can't open  
@XYMONHOME@/etc/cgioptions.cfg: No such file or directory, referer:  
http://iwr.ru.ac.za/xymon-cgi/svcstatus.sh?HOST=iwr.ru.ac.za&SERVICE=xymonnet
[Thu Aug 09 19:55:02 2012] [error] [client 41.145.0.228] Premature end  
of script headers: showgraph.sh, referer:  
http://iwr.ru.ac.za/xymon-cgi/svcstatus.sh?HOST=iwr.ru.ac.za&SERVICE=xymonnet

cgioptions.cfg exists and is readable by all in that folder!

I regressed rrdtool to 1.2 from 1.4 but it made no difference.  I did  
this because the showgraph build is optional on the DORRD keyword, and  
I thought maybe it wasn't being detected correctly, but there is no  
change, showgraph.cgi is still not built.  make output includes the  
symbol RRDTOOL12 instead of 'RRDTOOL'.

In my day of messing with this I managed to force showgraph.cgi to be  
built and I then manually installed it, and that is when 'internal  
server error' appeared instead of 'page not found'.

Any ideas?