Expected CHAR got NUMBER

Hi,

I'm getting an error (ORA-00932: inconsistent datatypes: expected CHAR got NUMBER) from the formula below. Which part of this formula is expecting a CHAR?

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select paf.assignment_id asg_id, ppf.person_id

  ,(ppf.last_name||' '||ppf.suffix||', '||ppf.first_name||' '|| ppf.middle_names) emp_name

  ,addr.address_line1||' '||addr.ADD_INFORMATION13 ||' '||addr.ADD_INFORMATION14 ||' '||addr.address_line2||' '||addr.address_line3||' '||addr.town_or_city||', '|| addr.region_1 || ' ' ||addr.postal_code emp_addr

  ,hou.name office

  ,hla.address_line_1||' '||hla.address_line_2||' '||hla.address_line_3||' '||hla.town_or_city|| ', ' || hla.region_1 office_addr