One of my WL books came available this morning but the sender PM'ed me to say her ISBN doesn't match that of my WL book.  After searching for her ISBN on PBS and Amazon, and finding no matches, I did a web search.  Her book comes up as a Target Club Pick.  Is this a book club book?  If not, and Target is just choosing certain books to promote, why the different ISBN?  Any ideas?

I don't know but she's posted the book incorrectly.  It should have been posted without an ISBN if the ISBN on the book didn't work.

I should go ahead and say.... I wrote her back and told her I would prefer to have the ISBN on my wish list and to please cancel the transaction so I can retain my place in line.  I haven't heard back from her and wonder what will happen when my time limit to respond is up?

You responded, told her you weren't interested in her copy, and asked her to cancel. You don't need to do anything else. If she doesn't respond and it times out, you'll go back to your previous position on the WL. If she ignores your request and sends it anyway, then you should mark it RWAP, and again you'll go back to the top of the waiting list.

If you didn't accept the WL offer then she can't cancel it.  If you let it time out you'll lose your place in line. You need to accept and them PM her again to please cancel and repost the book correctly.

I received a Walmart edition of a Mary Balogh book from PBS a year or so ago. I didn't notice it was a different ISBN until I went to post it. No big deal as it was the same story but the regular ISBN was wishlisted and it took me a while before someone found and requested my book since it had a different ISBN which wasn't wishlisted.

I always recommend putting a Tag on the main WL version to get those other versions moving.  Something like "Also under ISBN XXX".

Several publishers do have books with a different ISBN for book clubs, chain stores or for drug stores.   I think it might be used for market research and tracking.

Just to repeat what Mary said:

If you didn't accept the WL offer then she can't cancel it.  If you let it time out you'll lose your place in line. You need to accept and them PM her again to please cancel and repost the book correctly.

Thanks for the help.  I accepted and asked her to cancel.  She did and I've received my credit back and my place in line.  I also gave her some suggestions for posting her book correctly.  She informed me that she's been a member for several years and has had no issues with the way she does things.  She also advised me to start checking the PM for books I am offered so I won't request books from her bookshelf and have to wonder what she is mailing.  I guess it's just too much trouble for some people to follow the rules.

Is this why my edition of Dragon Tattoo appears not to be linked with the editions that are  Wish Listed?   My edition ( think I got it at Sam's club) has 50+ available copies?    

She also advised me to start checking the PM for books I am offered so I won't request books from her bookshelf and have to wonder what she is mailing

Wow, what a response.  You shouldn't have to wonder what book she's sending because she needs to be posting her books properly!  I guess she figures the requestor won't RWAP her as long as it's the same story.  If she's been a member for sevearl years and incorrectly posting books hasn't caught up with her yet, it should soon.