Error in UVM code

Hi,

I'm getting the following error when running the UVM code present in the following location. There is a sequence_item example which is present.

www.verificationguide.com/.../uvm-sequence-item.html

When i run it with the following command,

ncvlog -sv -uvmaccess -incdir $UVM_HOME/src mem_seq_item_example.sv

i'm getting the following error.

Can someone suggest why i'm getting the error ? I'm not importing the uvm_pkg in the code coz i've used "-uvmaccess" in the command.

Error I got is :

ncvlog: 14.20-s009: (c) Copyright 1995-2015 Cadence Design Systems, Inc.
class mem_seq_item extends uvm_object;
                                                                     |
ncvlog: *E,SVNOTY (mem_seq_item_example.sv,12|36): Syntactically this identifier appears to begin a datatype but it does not refer to a visible datatype in the current scope.

Suggestions are very much welcome.

~sree205.