R12.1.3 Error Page You have encountered an unexpected error. Please contact the System Administrator

Hello,

Please help. been reading here at the community but I cannot solve this issue.

Our user encountered this error when he tried to click on Self-service menu:

Error Page You have encountered an unexpected error. Please contact the System Administrator for assistance. site:community.oracle.com

Exception Details.

oracle.apps.fnd.framework.OAException: oracle.jbo.SQLStmtException: JBO-27122: SQL error during statement preparation. Statement: SELECT * FROM (select ppf.list_name full_name, hr_person_type_usage_info.get_user_person_type(ppf.effective_end_date, ppf.person_id) person_type, Decode(paf.assignment_type, 'C', hr_general.decode_lookup('CWK_ASG_CATEGORY', paf.employment_category), hr_general.decode_lookup('EMP_CAT', paf.employment_category) )employment_category, ppf.start_date, ppf.original_date_of_hire, decode(paf.period_of_service_id, null, pop.date_start, pos.date_start) date_start, decode(paf.period_of_service_id, null, pop.actual_termination_date, pos.actual_termination_date) actual_termination_date, Decode(paf.assignment_type, 'C', hr_general.decode_lookup('HR_CWK_TERMINATION_REASONS', pop.termination_reason), hr_general.decode_lookup('LEAV_REAS', pos.leaving_reason) ) leaving_reason, paf.effective_start_date, hr_util_misc_ss.getObjectName('JOB', paf.job_id, ppf.business_group_id, jtl.name) job, paf.job_id, orgtl.name organization, orgtl.organization_id, bgtl.name business_group, bgtl.organization_id business_group_id, lvl.location_code, hr_util_misc_ss.getObjectName('GRADE', paf.grade_id, ppf.business_group_id, gtl.name) grade, paf.supervisor_id, ppf.person_id, paf.assignment_id, paf.primary_flag, paf.assignment_number, ppf.employee_number, ppf.npw_number cwk_number, nvl(paf.effective_start_date, ppf.effective_start_date) Asg_start_date, decode(nvl(paf.effective_end_date, ppf.effective_end_date), to_date('31/12/4712','DD/MM/RRRR'), null, nvl(paf.effective_end_date, ppf.effective_end_date) ) Asg_end_date, hr_general.decode_lookup('YES_NO', paf.primary_flag) Prim_Flag, lvl.derived_locale, v.vendor_name Supplier, paf.VENDOR_ASSIGNMENT_NUMBER Supplier_id_assignment, paf.VENDOR_EMPLOYEE_NUMBER Supplier_id_worker, Decode(paf.assignment_type, 'C', hr_general.decode_lookup('HR_CWK_TERMINATION_REASONS', pop.termination_reason), hr_general.decode_lookup('LEAV_REAS',