Epson 3880 Prints Wrong Size Image (Solved!)

I'm about at wits end trying to figure out this problem with my Epson 3880 (plus wasting paper!). When I try to print using 17" wide paper, the printer prints only the bottom 8.5" of the image leaving the top half of the paper unprinted (it prints the entire long side). I have no problems printing at any other width. The printer is fairly new and I printed several 17" wide prints when I first got it with no problems. Apparently I've done something to change a setting somewhere. My printer settings are:

Under Page Setup: Size: 17" x22"
Under Page Layout: Paper Size: 17x22, Output Paper: "same as paper size", Reduce/Enlarge: Off, Optimize Enlargement: Off

I'm printing out of CS4 and my image size is set at 16" x 20".

I can't think of any other relevant settings. Any ideas?

As I recall from my previous Epson printers, they have very good tech support.
Why not give them a call?
Sandy

After several hours of over the phone with two different Epson tech support staffers consulting with the staff tech geeks while trying every possible solution (until they were literally this close to just sending me a new printer) we figured out the solution. It might be of interest to anyone using the Epson Pro 3880 with Epson Exhibition Fiber Paper. Turned out the problem was only with EFP paper (which is a fairly thick paper compared to most digital papers) and only with 17" wide paper. The solution was simply to turn off "Paper Size Check" under the printer menu (the factory setting is "on"). That's all it was, problem solved. I think I made Epson tech support history.