[ic] 500 errors on 2 admin screens

[Ben Levy]

Hi 

I've just installed Interchange 4.8.6 on a new server (redhat linux) and
got my existing shops up and running. The customer interface works
absolutely fine (as it has been on the previous server) and most of the
admin interface works. However, there are a couple of pages on the admin
side that are no longer working and give a 500 internal server error.
Nothing shows in the catalog error.log and in the server error log: 

[error] [client ...] Premature end of script headers:
/path/to/catalog/cgi-bin/cgi program 

This only occurs when looking at layout.html (Design - Layout Editor)
and order_view.html (Orders - individual order details).

If i delete all the information from the area table in the mysql db then
i can see layout.html... If i try and create a section I get the 500
error again...

I've checked access permissions and i'm logged in to the admin site as
the su. I have created a second su to check this. I've checked file
permissions, and i've removed the files in the session/ folder.

I have also created a foundation store to see if the problem could be
due to any code i've added to my stores, but the foundation store has
exactly the same problem...

Has anyone experienced this / have any idea what it could be. 

Any help would be greatly appreciated. 

Thanks 

Ben