Please use <code> tags around your code. This will preserve your formating and provide your readers with some bells and whistles.

#!D:/Perl/bin/perl.exe 
use Win32::AuthenticateUser;
@result = AuthenticateUser("domain", "smith", "abc123");
print @result;
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I ran AuthenticateUser() in the debugger to see what it does, and found that it returns the empty string '' (false) if the user is not Authentic, and 1 (true) if they are. I would run your script with the -w flag to get warnings. This way you would know that @result was defined when you print it. My suggested test code for you:

#!D:/Perl/bin/perl.exe -w
use strict; #always.
use Win32::AuthenticateUser;

# My version of Win32::AuthenticateUser did not export the function.
my $result = Win32::AuthenticateUser::AuthenticateUser(
             "domain", "smith", "abc123");
print $result ? 'Authentic User' : 'Unknown User or Password';
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