Update via API to PO_headers

Hello all,
I am trying to update po_headers via the api po_headers_pkg_s2.  I am building this in forms 10g on an R12 database.

I'm sure the fix is easy but I cannot see it.  The data in the field is text but I need to store a number in po_headers.

I get this error: expression is of wrong type.  Meaning text in a number field or vise versa.

I am sure my coding is terrible but please be gentle.

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  -- PROCEDURE update_docs_contact
  ------------------------------------------------------------------------------
  PROCEDURE update_docs_contact (p_header_id IN NUMBER)  IS