Unable to prostrct remove area - errors 8565 6961

Unable to delete a storage area from the database structure when removing the last extent fails with errors 8565 6961
Storage area has been truncated to the first extent with 'proutil -C truncate area'
The Storage Area is not the Schema Area
Unable to prostrct remove the last extent of an area - errors 8565 6961

All the database objects schema definitions have not been deleted from this area.

PROUTIL with the truncate area qualifier works by resetting the hi-water mark in the storage area back to the beginning of the storage area. 
This hi-water mark reset frees all of the space in the storage area for re-use. 
Any tables and indexes in the storage areas are initialized to the state they were in before they contained any rows or index entries. 

The tables in the area are still defined in the schema for the database. Deleting the table definitions must carried out in order to empty the extent, before it can be removed from the database structure with prostrct remove.

Delete the table definitions from the storage area through:

• The Data Dictionary
• Applying a "DROP TABLE" incremental .df with the Data Administration tool.
• Alternatively move the tables (and indexes if applicable) to another storage area with "PROUTIL -C tablemove"

For further information, refer to Article  How to Remove Storage Areas and Data Extents in Progress 9.x, 10.x, and 11.x