error fetching http headers when output to RGB instead of 256 colors

[Kenton Williams]

Hello,

I am working on a project in which we are using Cartoweb for a simple web interface.  I have a working, partially-completed project that can be viewed at www.geodatacommons.umaine.edu/cgddemo/cartoweb3/htdocs/cgd_mapfile.php

As you can see, I have added a satellite image layer, currently supplied by a 24-bit RGB GeoTIFF residing on the server.  I have also been able to get the JPL WMS global landsat mosaic to work in its place, but for the time being, the server's image
file is being used.

The problem is, when I switch from 256 PNG to any other output format with absolutely no other changes to my mapfile, the project fails, giving me the following error:

Failure

Class : SoapFaultWrapper
Message : Error Fetching http headers

When I simply switch back to 256 color PNG mode, the error disappears.  I have posted this error many times on the Cartoweb mailing list and even directly e-mailed the developers.  None of them can figure out why this is happening.

We are using a Debian Linux server and have all of the current updates to our software.  No matter whether the raster layer is present or not in my mapfile, switching to JPEG output (RGB) causes an error.  Using a WMS that specifically delivers JPEG
imagery results in the same problem if I change my mapfile output from PNG (256 color) to JPEG.

Does anyone have a suggestion on what may be causing this problem?  I've been wrestling with it for a week with no success!  

Thanks in advance!

Kenton Williams