Site map for error: "contains reference to entity but that entity was not found in the metadata cache"
Steps to follow:
You have to export your unmanaged solution .
Extract zip file to folder name with same name as of zip file.
check your sitemap by opening customization.xml.
search for entity name which is giving error.
if found comment that line.
Save customization.xml file.
now compress folder to zip file.
Reimport that zip file .