For cost center &/& no CO object has been defined at &

You worked on cost center &V2& in controlling area &V1&. No CO object
was defined for this cost center. Check this by displaying the cost
center in table CSKS using general table display. Select the
controlling area and cost center and display the object number as well.

System Response

You cannot make a CO-related posting or selection without an object
number.

How to fix this error?

The error is probably linked to the import of Release 1.2A and the
conversion of the CO data. The SAP System will run normally after the
update is imported and the conversion is completed.
If the termination occurred at another time, an internal system error
has occurred. Contact the SAP hotline service.

Error message extract from SAP system. Copyright SAP SE.