No output appears in the DBMS Output window when the DBMS_OUTPUT option is enabled.
1. Turn off DBMS_OUTPUT option.
2. Turn the DBMS_OUTPUT option on again.
3. Execute the script using the F9 key.
This issue was fixed in TOAD for Oracle 9.0.. The latest version of TOAD for Oracle can be downloaded at: http://support.quest.com/support_download/Downloads.asp