Do you really need to split the paragraph into lines? You can match a multiline string against a regex, too:

#!/usr/bin/perl
use warnings;
use strict;

$/ = "\n\n";

while (<>) {
    my @result;
    if (     /objectClass:\s+account/
         and /objectClass:\s+ifastUser/
         and my ($prods) = /ifastProducts:\s+(.+?)\s*$/mg # The /m is 
+important here.
         and my ($user)  = /dn: uid=(\w+?),./g) {
        push @result, $prods, $user;
        print join '|', @result;
        print "\n";
    }
}
[download]

But if you need the array, you can have it. The , $_) part of your code does nothing, so remove it. Here is my attempt to do what you need:

#!/usr/bin/perl
use warnings;
use strict;

$/ = "\n\n";

while (<>) {
    my @result;
    my @lines = split /\n/;
    if ( (    grep  /objectClass:\s+account/,                  @lines)
         and (grep  /objectClass:\s+ifastUser/,                @lines)
         and (my ($prods) = map /ifastProducts:\s+(.+?)\s*$/g, @lines)
         and (my ($user)  = map /dn: uid=(\w+?),.+/g,          @lines 
+)) {
        push @result, $prods, $user;
        print join '|', @result;
        print "\n";
    }
}
[download]