This REVOKE statement cannot be carried out. Either it revokes a database-level privilege, but you are not a Database Administrator in this database, or it revokes a table-level privilege that your account name did not grant. Review the privilege and the user names in the statement to ensure that they are correct. To summarize the table-level privileges you have granted, query systabauth as follows:
SELECT A.grantee, T.tabname FROM systabauth A, systables T WHERE A.grantor = USER AND A.tabid = T.tabid