Code review comment for lp:~zorba-coders/zorba/bug-1188061

Basically the same comments as the queue proposal:

1. Make the error QName variables %private;
2. Fix or eliminate the XQDoc for the error QNames;
3. Replace "node" with "item" in function XQDoc.

In addition:

4. You have a stray <p> at the beginning of the header XQDoc comment (diff line 21).

5. You have </p> in at least 8 places, instead of <p/>.