If the full exception is [InvalidOperationException: Could not find property 'defaultProfileItemID' on object of type: Sitecore.Security.Domains.Domain] you may have a compatibility issue with your Sitecore version.
Please check that you have the minimum required Sitecore version -
- Sitecore CMS 6.0.2 Rev. 090507 (Recommended minimum). This will ensure the defaultProfileItemId attribute is available in the domain configuration section.