I used the line from above and the line that returned to me is...

sh: -t: not found

below are the two programs, stripped down, that I am trying to run. The first one calls the second, which should print out the values. At this point all that I am trying to accomplish is seeing that the values get over.

Here are the two programs:
#!/use/bin/perl -w

open(EXT,"< LDB_EXTID.lst") || die "something";
while (<EXT>) {
   push (@externaluids, $_) || die "dead again";
}

close (EXT)

foreach $externaluid (@externaluids) {
    my $output = `ldbtest.pl -e $externaluid -t 123`;

    #for my testing purposes
    $counter++;
    exit if $counter > 10;
}

exit

#program ldbtest is simply...
#!/use/bin/perl -w
use Getopt::Std;
getopt ('et');

print $opt_e
print $opt_t

exit
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Lemme reiterate Malkavian's suggestion in Re: passing values to another perl program; as we can now tell from your posted code, you're snagging individual lines from the one file, and interpolating those values into your backticks; but as he suggested might be the problem, you've got newlines in there and so the -t is seen as the beginning of a new command. Here's one way to rewrite your code:

open (EXT, "LDB_EXTID.lst") or die "something";
my @uids = <EXT>; # read in each line as a member of the array
close EXT;

# here's the key line !
chomp @uids; # remove any trailing newlines from every member of @uids

foreach my $uid (@uids) {
    my $output = `ldbtest.pl -e $uid -t 123`;
    last if ++$counter > 10;
}
# stuff you'd do after the loop, if anything
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perl -e 'print "How sweet does a rose smell? "; chomp ($n = <STDIN>); 
+$rose = "smells sweet to degree $n"; *other_name = *rose; print "$oth
+er_name\n"'
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