UNVERIFIED SOLUTION i
The database purge script is accepting 'NULL' as Retention Days if not value is specified for same.
This is a know defect in the Purge script before EngageOne inform 5.0.
ResolutionUPDATED: September 14, 2018
This has been fixed in EngageOne version 5.0. As a workaround, in version before EngageOne inform 5.0, specify the 'retention days' explicitly.