When exporting BPM library from LCS and try to import it, it fails with below error:
"Excel file does not contain "Lines" worksheet."

The workaround for import is to download the template or to be sure you have a "Lines" worksheet as the Excel should be as per importing template.

The problem is that the export and import templates for BPM library are not compatible. It requires a manual work to edit export file, so it could be imported without errors.

This is a limitation of product and the BPM Library export and import operation should be compatible, so the export file could be used without additional manual editing.