Adding, then editing more than 50 feature classes in one ArcMap session causes the edits to fail. The error message displays:
"Oracle error ORA-01000: maximum open cursors exceeded"
This is a known issue.
Solution or Workaround
** 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. **