Error when uploading database

[Wezza007]

To update multiple products at once, I've tried downloading the products database as a text file and then finding and replace the text I need changed and then uploading the product file back over the original one. It all seems to go well, but at the end when I check the summary, I get some error messages. They say that a page could not be found and the product can't link to it.

Last time I did this, I had to go through the few products that couldn't link and manually link it to the page (which did exist but the Shopsite summary said they didn't). This time everything seemed to work fine, but I got the error message. I checked the products and pages and everything is correct, so I didn't need to do anything.

Why is this happening? I've attached a screen shot so you can see the message I'm getting: