does the other dog like puppies? Not other dogs...but specifically...puppies? Some adult dogs love puppies and others really really don't care for them...even if they adore other adult dogs.
Neutral territory is helpful...might bring the pup in in a crate and let the older dog sniff thru first to see what the vibe is...then lead the older dog away and allow the pup out...I find intro's go better off leash...be relaxed and happy...but also watchful for signs of trouble. Never carry a puppy in your arms around other dogs. I find this seems to cause a lot of trouble and jumping up and extra excitement, not a great idea.