In regard to the uploader - it was timing out when it was attempting to make a print ready file. This happened repeatedly.
That is not a printer problem though.
My files were "larger" in size, not in dimension. At first, I uploaded them at 600 dpi and then scaled them down to 300 for the second upload which is the one that printed perfectly. It was on my third revision that I started having problems with the timing out - even though the files were still smaller in size than the second upload.
There should be no problem with 600dpi images, although I use 300dpi.
I have been uploading PDF files which have images.
OK.
Lulu's "format" was something they told me I had to download. It's a setting for Photoshop to save the PDF "correctly" according to them.
Sorry, I have no idea what that format tool is, but then again I do not use the very dear Photoshop or PDFs, and I have no problems. But the way you describe it, you are using Photoshop to create PDF pages. Are you uploading your pages to Lulu one at a time then?
The problems I'm having is that I am the one who has to constantly make all of these changes when it is a printer problem. I'm trying to find a solution that does not involve using an obsolete product.
But as I say, you are describing problems from the word go, not just at the printer end.
I am glad you have sorted it out, but from what I can tell you have simply been suffering from doing it a very complex way. All that needs to be done is to create you images as jpgs matching the dimensions of your pages. Create a docx file of pages. Put the images on the pages plus Title & Copyright pages etc. Upload the file to the Wizard. 
