to be honest, I do not know. Probably you have very creative tool for interacting with Oracle. However it would be helpful, if you posted the exact error with its ORA numeric code (although the one you posted does not look like Oracle one - that "near" word comes from other RDBMS; are you sure it is from Oracle?).
Anyway, in standard Oracle sqlplus, the error is different:
SQL> CREATE TABLE EMPLOYEE_INPUT (
2 EMPLOYEE_ID NUMBER(6) NOT NULL,
3 FIRST_NAME VARCHAR2(20) NULL,
4 LAST_NAME VARCHAR2(25) NOT NULL,
ERROR at line 5:
ORA-00904: : invalid identifier
Yes, the last comma followed by nothing is the cause.