Purchasing Options--Security Hierarchy LOV

Hi
While setting up Purchasing in
Setup--Purchasing--Document Types the value for "Security Level" was set to "Public"

This was later changed to "Hierarchy". On this change a field "Security Hierarchy" was enabled in
Setup--Organisations--Purchasing Options--Control Tab

There are no values in th LOV and as such any other changes in the Purchasing options cannot be saved as the Security Hierarchy field is blank

How to populate values in this field


Thanks
Ninad