In reply to Harsha vardhan:
In errtest you have typo.
The callback type is:
derived_callback and not
derived_cb.
And you have an additional error in your environemnt line 28.
A uvm_error does not have a verbosity. It will be always displayed.
This line should be like this
`uvm_error(get_type_name(), "no config db object found")
See how it works here.