I have a restricted-use pdf document which requires a password for editing, but nothing else. On my desktop pdf reader it opens and reads just fine, no password needed for reading. On the N800 the pdf reader requires the password just to open and view the file. Is this a known limitation of the N800 pdf reader, that it doesn't distinguish between the different restrictions that can be placed on pdf docs?

gs (ghostscript) will print (or reconvert) to PDR sans encrypion. I would use this under windows/ cygwin.

I'm not familiar with this as a limitation of the N800 pdf reader (I just don't know one way or the other) but people talk about evince -- maybe that would read it. Alternatively, you ought to be able to get past the problem by decrypting it on your desktop. See, e.g., http://www.cs.cmu.edu/~dst/Adobe/Gallery/ and http://www.guapdf.com/ and, of course, you can google for more, similar solutions.