There is an oracle user who administers user accounts in an Oracle database. This user had alter, create and drop user privileges in the database. However when he clicks on "alter user" in the schema browser a message appear: "This process requires access to several DBA views".
Ask for the SQL Monitor to see which tables is Toad complaining about (let's assume that the tables are dba_table1 and dba_table2). Then grant the user (the user will appear in the SQL Monitor log as well, it is not necessary ask for it) as follow:
GRANT SELECT ON dba_table1 TO "USER"
GRANT SELECT ON dba_table2 TO "USER"