With beta 026, File > Export > Files, .doc format results in files that the iPad isn’t able to open – it gives a “Unable to Read Document, The file format is invalid” message. Note that when I export in either .docx or .rtf, iPad can open them, so something is fishy about the .doc exports.
Another oddity that I don’t whether it’s related or not: .doc exports are almost instantaneous, while .docx exports are rather time consuming, with an “Exporting files…” dialog box that takes about a minute to export 25,000 words on a fast PC. .doc happens in about 2 seconds on the same machine. So maybe the .doc exports are missing some required processing?