One PHP vs. Two Apaches (Wrong Content-type header .. )

Hello,

I installed Apache 2.0.47 with PHP 4.3.3 (as Apache
module). Everything worked fine, until I decided that I will install
one more Apache. I installed the second apache (again Apache 2.0.47
and PHP 4.3.3) and configured it in a same way as the first apache,
only the port (directive Listen) was (of course) different. From that
time, strange think is happening. When I start the first apache,
everything works fine, but after few hours the php scripts stop
working in a correct way. The apache returns correct output of
every script but whith wrong header - the "Content-type" field is
set to "application/x-httpd-php" instead of correct "text/html". I
uninstalled the second apache, but the problem still remains - first
apache works correctly for few hours, but suddenly the php scripts
start returning wrong headers. I have made following perl script:

#!/usr/bin/perl

while( 1 ) {
$str = `netcat -w 2 [MY IP ADDR] 80 < /root/GET | grep 'x-httpd-php'`;
if( length( $str ) ) {
system( "/usr/local/apache/bin/apachectl stop" );
sleep( 4 );
system( "/usr/local/apache/bin/apachectl start" );
}
sleep( 60 );
}

This script makes it eayser, but I would like it to be like it was,
before I installed the second Apache. Do you have any idea, where the
problem might be?

Thanks
JV