SQL & PL/SQL

I am honestly confused on this one...

When I run the following in sqlplus:

SQL> SELECT a.fname, a.lname
FROM h_user_m a
WHERE a.id IN
(SELECT UNIQUE m.user_id
FROM h_user_role m
WHERE m.role_id =
(SELECT UNIQUE id
FROM h_role_n
WHERE LOWER (name) = 'wc-ismp-admin')
OR m.role_id =
(SELECT UNIQUE id
FROM h_role_n
WHERE LOWER (name) = 'wc-ismp-user'))
AND a.id NOT IN (SELECT user_id
FROM ip_user);

ERROR at line 2:
ORA-22806: not an object or REF

I run the same query in Toad for Oracle v9.7.2.5 and it returns the same error, but highlights the reserved word FROM. I googled the error, but I'm not for sure why the reserved word FROM would be causing the error?