New Post: Importing catagories only

Hello,
how can I import categories only? I edited the categoryCSV.ImportMapping template and created the corresponding csv file with one category to test it. The import has run, but:

• The system creates an additonal "imported" category
• The category, which is supposed to be a subcategory, is at root level and the system throws this error: >Imported: 1 Products

Imported: 1 Categories
Product Ref: "8" failed to import.

"8" is supposed to be the categoryid of the parent category. What am I doing wrong? Shall I use parentname instead of parentcategoryid?

Thanks

Franco