Gerac7,
Did the wing fail at the joint or outside the joint? Did you remove the covering on the face of the ribs? Did you test-fit and notice if the wing joiner was loose in the joiner box? Did you use 30 minute or 6 minute epoxy when you joined the wing? Was your first landing a little hard? I know this sounds like an interrogation, but all these things are valid, important questions.
About 1/4 of the glueing surface area of the wing root is lost because of the covering...and since its on the outside of the root makes it even worse. The manual doesn't mention removing the covering. I re-read the section on joining the wing. If the wing joiner does not fit snug in the joiner box, you are depending on the epoxy alone for strength. As soon as the joiner is subjected to enough stress, the epoxy fails causing the joiner to slip, resulting in the covering peeling away from the wing root. The rest is academic. 6 minute epoxy doesn't penetrate the wood like 30 minute. If the joiner is snug, it should not move and the wing should be able to withstand more stress. Fiberglassing the center section would increase the wing's strength as well.
Whenever I buy an ARF, I do some research out here on RCU and RCGroups. I learn what others have experienced and apply whatever I think will correct.

Thanks
CAsniffer