DECLARE
p_employee_number number := 2000121;
BEGIN
apps.samir_test.samir_test_p ( p_employee_number);
END;

I get following error.

ORA-06550: line 7, column 3:
PLS-00905: object APPS.APPS is invalid
ORA-06550: line 7, column 3:
PL/SQL: Statement ignored
I wonder if this related to Oracle security. You might need to manually grant apps access to the package if you specify the schema owner, even if that is you. But because users can't grant themselves anything have sys do an explicit execute grant on this package to apps and try the original test again.