Now I have figured out the major part of the problem here. I have an entity with an annotation like @Name("invoice") and then, in my dataTable, I have var="invoice", and that is bad bad bad because somehow it isn't being found or whatever. Moral of the story: Use separate names for the variables in your dataTable iterators as you have in your various contexts. It might work or it might cause a debugging nightmare. I need to get used to the namespaces of Seam. I do wish there were some good debugging utility that would let me see this stuff, but anyway.
For the benefit of Google: I googled for this exception and noticed that I'm the first to mention it in any forum or anywhere, so anyone else who gets it will find this page and should look in their jsps for this. The exception is:
Caused by: java.lang.IllegalArgumentException: value of context variable is not an instance of the component bound to the context variable:
Thank you. Your post help me very much !!