When you click on the reference where does it take you? Does it take you
somewhere other than where it should go? If so then you need to replace the
reference(s) so that they point to the correct location. If on the other
hand you end up where you expected, is the clause number correct or is it
"0"? If it's "0" then you need to fix the paragraph numbering for that
paragraph/style, but if the clause number is correct then you'll have to
replace the reference because it may be corrupt (unlikely) or referring to
something other than the paragraph number. Another thought - the reference
may be to a level that starts at 0 but the reference may be "no context" so
if you've got levels like this:
1.
1.0 and your cross ref is to this para
1.1
etc
then your reference would be "0" because a no context reference would leave
off the "1". In this case you'd need to replace the reference with one that
is full context.
HTH