var percentual = parseFloat(search.lookupFields({
                        type: 'customrecord_rsc_desconto_forma_de_parce',
                        id: currentRecord.getValue({ fieldId: 'custbody_rsc_forma_pg_st' }),
                        columns: ['custrecord_rsc_desconto_aplicado']
                    }).custrecord_rsc_desconto_aplicado) / 100

{"type":"error.SuiteScriptError","name":"SSS_MISSING_REQD_ARGUMENT","message":"search.lookupFields: Falta um argumento necessário: id","stack":["createError(N/error)","beforeLoad(/SuiteScripts/rsc/user event/rsc_eventuser_parcelamento_invoice.js:47)","createError(N/error)"],"cause":{"name":"SSS_MISSING_REQD_ARGUMENT","message":"search.lookupFields: Falta um argumento necessário: id"},"id":"","notifyOff":false,"userFacing":true} I'm having this problem. But I did not understand. I assume I must pass only the field ID.

currentRecord.getValue({ fieldId: 'custbody_rsc_forma_pg_st' })

<-- log that value

typeof is helpful.

the error indicates that the value you are passing as the id parameter is empty and the id is required to lookup the record

Thank you guys. I will try to follow the suggestions