Server error retrieving coverage via WCS

[Vincent J. Troisi]

I am trying to retrieve an entire layer of a tiled Geotiff mosaic
using the WCS protocol. In some cases if I request a subset of the
layer, I am successful. I am unsuccessful when I near a request the 
entire area.
The error is:

> The server encountered an internal error and was unable to complete 
> your request.
>
> Error message:
> Premature end of script headers: <name of the WCS cgi script calling 
> mapserv>
>

We are using mapserver 4.6. The layer is 16-bit raster. Each pixel 
represents
a 125x125m surface resolution. The extend is
-3174450,-2816050,2867175,2406325

I attempted to retrieve the layer/image with ResX and ResY set to 250
(enhancing the resolution by 2). The request was successful, but the
values in the retrieved file were all 0.

Any suggestions...