InnoDB: Error (no replies)

windows XP 32, (mysql-5.1.51-win32.msi)

101017 2:31:55 [Note] Plugin 'FEDERATED' is disabled.
101017 2:31:55 InnoDB: Error: unable to create temporary file; errno: 2
101017 2:31:55 [ERROR] Plugin 'InnoDB' init function returned error.
101017 2:31:55 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
101017 2:31:55 [ERROR] Unknown/unsupported table type: INNODB
101017 2:31:55 [ERROR] Aborting

101017 2:31:55 [Note] C:\Program Files\MySQL\MySQL Server 5.1\bin\mysqld: Shutdown complete

Why?