Thanks Mark. Did you use steel or zinc-plated corner braces? It also looks like yours are like 5 or 6 inches in length as they don't reach out very far. If so, that is good news.
Looks like it is back to the home improvement store, get the corner braces, and do some re-measurements.
I'm also going to order one of those Dowel-It's online to see it up close and in person.