I would double coat that dam!! I had one this week end that oozed all night and I was up to 3:00 in the morning fixing it... never really did.
I don't want to scare you.... just don't worry about getting that filling all the way out to the edge.. keep it inside and have your icing thicker than what you want to spread with so it can withstand the weight.....
I am such a chicken with strawberry filling. I mix just a little bit of buttercream in it to help it stay put and not bleed. Then an extra big, extra stiff bc dam.
If vegetarian concerns are not a problem, then sprinkle 1/2 T of gelatin (1/2 package) over 2 T cold water. Let it thicken a minute or 2, then warm the preserves very gently (if you use a microwave, really lower the setting, because sugar gets hot fast), then blend in the gelatin. Let it set up. It's good to do this early, while perhaps your cake is baking. When cool, it's ready to go! 
This stabilizes most preserves and avoid a lot of leaking. But, yes, the icing ring/dam is a must! A stiffer icing (add more powdered sugar) helps a lot.
http://www.wilton.com/cake/cakeprep/stacking.cfm
Hope this helps!
I used the sleeved strawberry pastry filling with about a 1/2" dam, it will not run, ooze, or soak into the cake. I also torte all my layers so instead of having one thick layer of filling, I have 3 thinner layers, helps with stability. A thick layer can cause the layers to slip.
Jenna - As JoAnnB said, "Also, don't add too much, or the weight will squeeze out the filling." I got carried away with filling just recently; and while the dams held and it didn't bluge or leak on the sides, the cake was totally unstable. I couldn't get it frosted properly because each layer threatened to slide off. Once it was cut, the top two layers did slide off. The intact dams were the only thing holding it together.
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