I had the same problem. This worked for me when trying to import blog posts form Wordpress after exporting the XML from wordpress manually and uploading to Squarespace.
Go to Trash - the import should all be there - and restore it.
Go to your Pages and you should see it greyed out under Not Linked.
Clock the drop down, Select All, and then Move to a NEW Blog page.
No idea why this worked, but it did.