Hi Paul, thanks for your advice. I will say that even though I am no bike mechanic, I have removed plenty of rear wheels and this was the first time I was unsuccessful. I am taking it to the folding bike shop where I brought it and will sit with the mechanic while they remove it so I can see how it's done. At this point, I'm too frustrated and I don't want to inadvertently damage my beautiful new bike.
Do you (or anyone else reading this) have any thoughts about a front rack for carrying stuff? To me it looks like a better solution than the cross-rack. Also, I am very pleased with the water bottle cage I installed on the stem. It makes a convenient hook by which to hang the handlebars off the top tube when the bike is folded.