RH -> Debian migration breaks CGI script under Apache

["Mark Calleja" <m_c_001@hotmail.com>]

I've recently upgraded our webserver from RH 7.3 to Debian "etch", installed 
Apache2 and all seems fine, except one CGI script no longer functions 
correctly even though as far as I can tell I've reproduced the Apache 
configuration options on the new machine. At the nub of it, the relevant 
section can be boiled down to the following snippet of code, which involves 
setting a signal handler for an alarm:

 eval
 {
   local $SIG{ALRM} = sub { die "alarm\n" };
   alarm (TIMEOUT);
   system "<a system call is executed>";
   alarm (0);
 };
 die if $@ && $@ ne "alarm\n";     # propagate errors

 # Did we timeout?
 if ($@)
 {
   system "<perform some cleanup>";
   print "Timed out";
 }
 else
 {
   print "OK";
 }

This worked fine as a CGI script on the old RH box, and will work on the new 
Debian box from the command line but not when run as a CGI script. In the 
latter case, the alarm never fires and the process waits on the first system 
call to complete.

Is there some subtle bit of Apache configuration that I may be missing to 
make that pesky alarm call work? Or is there something not quite right with 
Debian's Apache2 package?

Ta for any help/clues,
m