Mangled HTTP response?

I've installed Squid under Linux (Squid Cache version 2.3.STABLE1 for
i686-pc-linux-gnu) and am using it as a transparent proxy. Some
of our servers for internal use have adminstration CGIs (these are the only
pages so far with this problem), and apparently at random will ask the browser
to save the reply instead of displaying it.

A look at the saved file under Linux using a hex dump is this:

0000000 \0 \0 \0 \a \0 \0 \0 004 \0 \0 \0 \0 \0 \0 \0 \0
0000020 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0
*
0000060 \0 \0 \0 \0 H T T P / 1 . 0 2 0 0
0000100 O K \r \n S e r v e r : A p a

For some reason, there are about 140 null and/or other binary characters
printed before the HTTP response headers.

Does anyone know what causes Squid to do this, and how I can fix it?

-- 
Adrian Daminato 
Tucows International Corp.