When mapping fields to salesforce.com, Gravity Forms attempts to make it easy by automatically matching keywords such as 'name', 'company', 'email', 'phone', and 'fax' to the standard salesforce.com objects. The problem is that sometimes these fields are required to use words with that match these keywords, but map to a custom field. For example, in Gravity Forms we have a field labeled 'Qty of Phones:'. This field needs to map to the 'Qty_Of_Phones__c' custom field in salesforce. Instead, this field is putting a value into the 'Phone' field in the salesforce.com record. Entering the custom field name into the 'Admin Label' or the 'Parameter Name' does not seem to work as expected.
To fix this I suggest overriding the automatic matching in the 'Field Name' by making either or both the 'Admin Label' and 'Parameter Name' an override value. If there is a value in one of those fields that matches an object in salesforce.com, then the application should use that field regardless.