I think the problem is that the perl gtk binding uses the old version of gtk library but the schema is migrated to the version in Quantal and the location of the key changed and is now in com.canonical.desktop.interface.scollbar-mode
I think the problem is that the perl gtk binding uses the old version of gtk library but the schema is migrated to the version in Quantal and the location of the key changed and is now in com.canonical. desktop. interface. scollbar- mode