In reply to chris90:
That is not the correct way to prevent this error. The correct way is to use SV Packages.
package agent_pkg;
import uvm_pkg::*;
`include "uvm_macros.svh"
`include "seq_item.sv"
`include "seq_driver.sv"
`include "seq_monitor.sv"
`include "seq_agent.sv"
endpackage
Then you should import agent_pkg where required.
See this article for more information.