Thank you all for your help. The reason why I'm putting a bit of code into the SUBS package is that I've got about 5 different CGI scripts which get information out of SUBS - it saves me repeating alot of code. My solution was as follows. In SUBS:

package SUBS;
use Exporter;
@ISA = qw(Exporter);

@EXPORT = qw ($log $site $base $dbh);

use vars qw  ($log $site $base $dbh);

sub connectdb() {

  #Open the Oracle database:

  my($dbline,@dbinfo);
  if (!defined(open(DBINFO, "$base/dbinfo"))) {
    die "Can't open dbinfo.\n";
  }

  while(defined($dbline = <DBINFO>)) {
    chomp($dbline);
    push @dbinfo, $dbline;
  }
  close(DBINFO);

  $dbh = DBI->connect($dbinfo[0],$dbinfo[1],
                  $dbinfo[2],$dbinfo[3],
                      { RaiseError => 1,
                        AutoCommit => 1}
                     );

  $dbh->trace(2,"$log");

  }
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While in db.cgi:

package SUBS;
use SUBS;
.
.
.
&connect_db();
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The main difference betwee this example and my original post was that I am now using use SUBS as opposed to require SUBS as before. I'm also using 'use var'. SUBS also now exports only those variables used by db.cgi in the @EXPORT array. Again, thanks for all your suggestions.
Stacy.