ORA-22806: not an object or REF on the reserved word FROM, how to debug?

Question

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?

Answer 1

Thank you for the quick response.
I tried your query and I still receive the same 'ORA-22806: not an object or REF' error & in Toad, it does highlight the reserved word FROM.
Oddly enough, I went back and ran the first sub-query from both of our SQL statements and no errors returned.
Only when I added the sub-query back to the main query I receive the error as mentioned.
So, the following worked:
select m.user_id
from h_user_role m
where m.role_id in
(select id
from h_role_n
where lower (name) = 'wc-ismp-admin'
or lower (name) = 'wc-ismp-user'
minus
select user_id
from ip_user)
but added back to:
select a.fname, a.lname
from h_user_m a
where a.id in(...)
The error returns - the same steps apply to my statement as well...
Looking at the 10g Release 2 (10.2) documents, I don't see any restrictions to the IN reserved word, in terms of number of sub-queries, etc...