When i try to create / edit a feature class, i get following error.
Feature class is versioned.
Using ArcGIS 10.1, Oracle 11g
Create: an unexpected failure occurred.
Underlying DBMS erro ORA-01036
Modify feature: an unexpected failure occurred.
Underlying DBMS erro ORA-01036
/blogs/dan_patterson/2016/05/09/the-links contains an 'issues addressed' set of links. It might be worthwhile going through those links for specific fixes associated with newer versions or search on Esri Support Home since your software version is quite old. The chances of someone remembering that particular error is quite slim. This of course assumes you have searched on GeoNet and turned up nothing using keyword phrases like 'featureclass is versioned' or on your combination of software.
Addendum
You seem to be having ongoing issues with the combination of software you are using...
https://community.esri.com/thread/187059-script-tool
checking the updates and bug fixes with version changes may be prudent
What type of geometry format you are using SDEBINARY , ST_GEOMETRY or SDO_GEOMETRY?
SDO_GEOMETRY
Hi Jaya - Are you editing a version of the database?
-Adam Z
Try to create the same feature class with ST_GEOMETRY type. Does it have the same problems?