Looks like the rental property listing for $1,200 "expired" on 12/31/11. Your agent was only offering $100 to a Realtor who brought a tenant. It's customary to offer at least 25% of the first months rent or $300 on a $1,200 property.
If you decide to list it again with a Realtor, you may want to make sure there is ample incentive for a tenant's Realtor to take her time to show her client your rental listing. Some Listing Realtors will try to keep the majority of the commission for themselves and not adequately share with another Realtor. Many Realtors will simply bypass showing your rental listing because the $100 will barely pay for the gas for her car to cart around a prospective tenant.
All the best,
Alma Rose Kee PA
Future Home Realty