** This has been resolved in ArcGIS 9.1 **
During reconcile, the error: "ORA-01747: invalid user.table.column, table.column, or column specification" may occur after editing Geometric networks.
This is a known issue.
** This issue has been addressed in ArcSDE 9.0 Service Pack 3 (SP3)
Click on the link in Related Information below to download the Service Pack, if necessary. **