>I'm having trouble with an SQL statement that creates a temp dbf. Its a standard statement Select * From...
>Sometimes the created file ise set to exclusive use, and sometimes its not. This occurs even if I set exclusive off and then close and reopen the temp file. Any Clues?

Normally all temporary files/tables created for exclusive usage, and logically it's right because this is strictly local file. If you close and reopen dbf file with command USE ... SHARED it must be open as shared. And in faxt it's not temporary file.
May be your meant cursors? These are really temporary tables.