From The Document Foundation Wiki
Open the context menu next to the entry for your table on the left of the Base data navigator and choose SQL. In the window which appears insert
GRANT ALL ON <tablename> TO <username>
and execute the statement. Now your table should be editable.
- The driver that you are using is not up to date. In old versions of ODBC it canbe that the privileges and name of the current user aren't correctly displayed.
- Base is still connected (following a bad shutdown, for example). To disconnect it, you'll have to go to the directory where the database is held and remove the file whose extension is .lck.