I have a book "90 minutes in Heaven",   ISBN 10 : 0800759494  .  There are 40+ people wishing for the book, but my book isn't moving.  Why is that? 

Is the ISBN the same? If the ISBN is different then it won't get offered to the people who have another version on WL.

Or is it just cycling through wishers?  Sometimes that happens. 

The copy of the book that uses your ISBN doesn't have any wishers. Other versions do have wishers. You have a few choices. You could tag some of the wishlisted ones with the ISBN for yours, stating that you have another version, or you can list in your signature, or you can go to the genre forum and post a "Is This On Your Wishlist" type message. There are a number of versions that are available in the system and others that are not. One of the most widely WL'ed versions doesn't even appear to have a valid ISBN. (It's only 6 digits or so.)

Good Luck!

ok - thanks for the suggestions.  I will try them.  I have posted books in the bazaar, but that is so time consuming.

I get your first and third suggestion  but what does it mean "to list in your signature"

If you go into settings you can put a message that shows up in your signature when you post.  LIke where mine says my recent reads.  Putting something in your signature really only works if you are a regular poster.