Expense Report error

When user click on Create Expense Report, getting following error.

Exception Details. oracle.apps.fnd.framework.OAException: oracle.jbo.SQLStmtException: JBO-27122: SQL error during statement preparation.

Statement:

SELECT * FROM (SELECT lookup_code lookup_code, meaning description

FROM fnd_lookup_values_vl

WHERE lookup_type = 'HOME_OFFICE'

AND AP_WEB_DB_HR_INT_PKG.isPersonCwk(:1) = 'N'

UNION

SELECT TO_CHAR(vendor_site_id) lookup_code, vendor_site_code description

FROM ap_supplier_sites

WHERE SYSDATE < NVL(INACTIVE_DATE, SYSDATE + 1)

AND NVL(pay_site_flag,'N')='Y'

and vendor_id is not null

AND vendor_id = (SELECT paaf.vendor_id

                          FROM per_all_assignments_f paaf