#!/usr/bin/perl

my $greeting = $ARGV[0] // '********** PERL RECEIVED A NOTIFICATION:';

sub my_receiver {
    print $greeting, "\n";
}

NetSNMP::TrapReceiver::register("all", \&my_receiver) || warn "failed to register\n";
print STDERR "Loaded the example perl snmptrapd handler\n";

##</code><code>##

perl do "/usr/local/share/snmp/mytrapd.pl hello";

##</code><code>##

That won't work.  The perl 'do' command only expects a filename.

Instead, you can either define a subroutine in the file rather than have
the file itself do something.  IE, in the file if you put:

sub foo {
   print "$_[0]\n";
}

and then put these lines in the snmptrapd.conf file:

perl do /path/to/script
perl foo("hello world");
perl foo("now I am passing something different");