Sync Lead to SFDC caught exception

[Anonymous]

I am getting this exception when attempting to sync a new lead to SFDC: Failed: FIELD_CUSTOM_VALIDATION_EXCEPTION: Invalid country name. Please use standard country names (USA, United Kingdom, United Arab Emirates, P.R. China...)

I have removed the country field from the Marketo form entirely and am still getting this error when I test on a new lead. So even when the country field is blank I am getting this error - any thoughts?

[Anonymous]

Removing the field from Marketo makes the problem worse than it already is. The solution is normalising the country names in the lead record, matching the names in use by SFDC.