hyperlink reference not valid
 

I have created named ranges in the name box on the formula bar, no problem
with this, in another work sheet i have created several hyperlinks that link
to the same ranges within the name box, which appear in the box when
selecting hyperlink or edit hyperlink.. the links work for a while then after
a short while i''m gettin error message when i clik on the link ' Reference
not Valid' i then edit the link again and it works but then the the same
message returns after a while.. Any suggestions?