Hi Wendy... try the following 3 things in order. If the first doesn't work then try the second etc..
1. In DataSource Maintenance try using the delete tab on the left side of the datasource record.
2. In the Webspeed workshop pull up the tables for CSS. In wpro_dataSource table select the record and select the delete key.
3. In MFG/PRO Progress editor, connect to the qadcss db then delete the wpro_datasource record using a progress query on the table.
4. If you are unsure of any of these steps please contact support.