Inventory > INV.MTL_MATERIAL_TRANSACTIONS Show Error Msg: ORA-20100: File lxxx.tmp creation for FND_FILE failed.

Fixed Step.

1.  Backup error data

CREATE TABLE MMT_BACKUP_0805 AS
SELECT *
FROM INV.MTL_MATERIAL_TRANSACTIONS  MMT
WHERE MMT.TRANSACTION_ID IN (
12883636
,12883651
);

2.  Close Cost Manager

Inventory > Request > (find) Cost Manager (B: Cancel Request)

Inventory > Setup > Transactions > Interface Managers

Now, the Cost Manager stauts: Inactive

3.  Update error data

UPDATE MTL_MATERIAL_TRANSACTIONS
SET COSTED_FLAG = 'N',
     REQUEST_ID = NULL,
     TRANSACTION_GROUP_ID = NULL,
     TRANSACTION_SET_ID=NULL,
     ERROR_CODE = NULL,
     ERROR_EXPLANATION = NULL
WHERE 1=1
AND TRANSACTION_ID IN (
12883636
,12883651
);

COMMIT;

4. Restart Cost Manager

Inventory > Setup > Transactions > Interface Managers (Menu: Tools > Launch Manager)

5. Checking the error data posted to Cost Accout

SELECT *
FROM INV.MTL_TRANSACTION_ACCOUNTS MTA
WHERE MTA.TRANSACTION_ID IN (
7647820
,12883636
);