Are you on Procurement 12.1.3 and using Oracle Time and Labor (OTL)?
By LuciaC-Oracle on Jan 09, 2013
Apply the fix to avoid the following issue when attempting to cancel purchase orders:
APP-FND-01934: ORA-01403 no data found in Package PO_HXC_INTERFACE_PVT Procedure CHECK_TIMECARD_EXISTS
This error occurs after applying Patch 10281212 R12.HR_PF.B.DELTA.4.