The code you have posted seems to work fine to the extent I can test it. I left out the sub Startup ... and made 3 changes:

#use System::System_Constants;
...
our $progname = q{Constants::APPLICATION_SERVICE_NAME_SHORT};
...
#Log("\n ProgName: $progname \n");
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I simply tested with:

$ cat pm_perlsvc.pl
#!/usr/bin/env perl

use strict;
use warnings;

use PerlSvc;
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which produces

$ pm_perlsvc.pl
Path: /Users/ken/tmp/pm_perlsvc.pl
Program Dir: /Users/ken/tmp/
Logfile: /Users/ken/tmp/SCC_Service.log
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I see you've used File::Spec->splitpath() to get the path elements. For portability, I would recommend using File::Spec->catpath() rather than the concatenation operator (.) when joining path elements.

You haven't shown the code where you are attempting to call PerlSvc::Startup() which makes debugging from this end rather difficult.

I notice a lot of variables declared with our. If they need to be declared like this, check that you're not modifying $PerlSvc::path, $PerlSvc::directory, etc. outside of the PerlSvc package; if our $whatever is not a requirement, change it to my $whatever.

If none of that helps, post the code with the call to PerlSvc::Startup() for a better answer.