FND_VIEWOBJECT_NOT_FOUND. Tokens: VONAME = XxPoNotifHeaderSummaryVO; APPLICATION_MODULE = oracle.
Hi All, 
I´m working on a customization of po approval notification.
After extending PoNotifHeaderSummaryVO and successfully importing it , then adding new field by clicking link  "Personalize Document Details".
I´m receiving 
Message not found. Application: FND, Message Name: FND_VIEWOBJECT_NOT_FOUND. Tokens: VONAME = XxPoNotifHeaderSummaryVO; APPLICATION_MODULE = oracle.
Note: I extended PoNotifLinesSummaryVO without issues. 
Please advise!
