Over at azurecurve, Ian Grieve hunts down Check Remittance Run-time error ’13′ – Type Mismatch
Check Remittance Run-time error ’13′ – Type Mismatch | azurecurve
Payables & ReceivablesInstall, Upgrade & AdminMicrosoft & the GP Ecosystem
Archived post from 2011. Dynamics GP and the links it points to have changed since; check current documentation before relying on version-specific steps.