Problem with Subquery

We recently changed our database system from Oracle 8i to postgreSQL. Im
right now changing our cold fusion code and i have get this problem:

select ID,
NAME,
WEBSITE_URL,
(
select count(*)
from MAIN_PC_GAME,
MAIN_COMPANY
where DEVELOPER_ID = MAIN_COMPANY.ID
or PUBLISHER_ID = MAIN_COMPANY.ID
) as TOTAL
from MAIN_COMPANY
where (
lower(SOFTWARE_DEVELOPER)='yes'
or lower(SOFTWARE_PUBLISHER)='yes'
)

This SQL statement isnt working with postgreSQL but it worked without
any problems in Oracle. Postgres Error Message:

Unable to identify an operator '=' for types 'character varying'
and 'numeric'
You will have to retype this query using an explicit cast

I think postgreSQL cant handle the variable MAIN_COMPANY.ID from the
parent Scope. Probably there is a way to mark this variable to find it
in the caller.scope. But i dont know how.

Marc Polatschek
Head of Development
COMPUTEC MEDIA AG
Dr.-Mack-Straße 77
D-90762 Fürth
phone: +49 (0) 911 2872 - 106
fax: +49 (0) 911 2872 - 200
mail: marc(dot)polatschek(at)computec(dot)de