Doh. Should have waited.

It seems to have something to do with hosts with a client that reports full details, ie, disk, cpu, memory etc.

I have some hosts doing ping only tests, info column is fine. Info column on Windows and Solaris clients that report in fail with a similar apache error eg.

[Wed Jul 23 08:34:18 2008] [error] [client 10.10.10.2] Premature end of script headers: bb-hostsvc.sh, referer: http://hobbitmon.example.com/hobbit/Solaris/Solaris.html

Craig