Hyperlink not staying Active

Hello,

I just upgraded to 2007 and can no longer hyperlink to sheets in the same
book more than once. My first sheet is a key/index to all the other sheets
in the file. For years I have created a hyperlink (in 2003) from the
key/index sheet to each other sheet. Regardless of the number of times the
link was clicked I would jump from the key/index sheet to the desired linked
sheet. Now a new hyperlink seems to work only once, and 99% of the old links
do not work at all (a couple of old links worked once).
Thanks,
--
IDI