"When you redefine a method, you cannot change its visibility (PUBLIC, PROTECTED)"

Dear experts,

I support an application on SAP BW 7.31 - after migrating form 7.0 to 7.31 we get this error.

In the debugger I came to an instantiation of the object of type ZCLASS wich fails with the error above.

Create object obj_ref...

The class ZCLASS is a subclass of CL_RSSH_HIERARCHY_BASE.

I seems to me SAP changed something in the base class wich affects our subclass now.

Can someone give a hint?

What does the error in general mean?

Thanx in advance

yk