InfoPath Dev

I get the following error when using an external list infopath form in sharepoint 2010. The form has a external item item picker which when populated, seems to be causing this problem. Leaving the external picker empty allows the form to submit without errors.

ItemPicker: Exception occurred while calling FindSpecific: System.Runtime.Serialization.SerializationException: Attempting to deserialize an empty stream.     at System.Runtime.Serialization.Formatters.Binary.BinaryFormatter.Deserialize(Stream serializationStream, HeaderHandler handler, Boolean fCheck, Boolean isCrossAppDomain, IMethodCallMessage methodCallMessage)     at Microsoft.SharePoint.WebControls.ItemPicker.get_ExtendedData()     
at Microsoft.SharePoint.WebControls.ItemPicker.get_EntityNamespace()     at Microsoft.SharePoint.WebControls.ItemPicker.get_BdcEntity()     at Microsoft.SharePoint.WebControls.ItemPicker.ValidateEntity(PickerEntity pe)	58502b0d-4692-4f42-8ec5-8eb39806dbc3

02/20/2013 09:58:14.20	w3wp.exe (0x0128)	0x11DC	SharePoint Foundation	General	72b7	Medium	Error validating entity 1: 
System.Runtime.Serialization.SerializationException: Attempting to deserialize an empty stream.     
at System.Runtime.Serialization.Formatters.Binary.BinaryFormatter.Deserialize(Stream serializationStream, HeaderHandler handler, Boolean fCheck, Boolean isCrossAppDomain, IMethodCallMessage methodCallMessage)     
at Microsoft.SharePoint.WebControls.ItemPicker.get_ExtendedData()     
at Microsoft.SharePoint.WebControls.ItemPicker.get_EntityNamespace()     
at Microsoft.SharePoint.WebControls.ItemPicker.get_BdcEntity()     
at Microsoft.SharePoint.WebControls.ItemPicker.ValidateEntity(PickerEntity pe)     
at Microsoft.SharePoint.WebControls.EntityEditor.Validate().	58502b0d-4692-4f42-8ec5-8eb39806dbc3
02/20/2013 09:58:14.20	w3wp.exe (0x0128)	0x11DC	InfoPath Forms Services	Runtime - Business Logic	82g1	
Critical	There was a form postback error. (User: DIR\kpidev, Form Name: Template, IP: , Request: http://kpi-web/dataentry/Lists/Organization/Item/newifs.aspx?RootFolder=/dataentry/Lists/Organization&IsDlg=1, Form ID: urn:schemas-microsoft-com:office:infopath:entity:-AutoGen-2013-02-14T20:55:37:445Z, 
Type: SchemaValidationException, 
Exception Message: Schema validation found non-datatype errors.

What can I do to fix this?

Hello Sri,

Probably has to do with the data type for the external picker not matching the data type in the form.  From the error message it seems that the InfoPath control is trying to get a value from the external list but it isn't matching or isn't deserializable.

What control are you using in the form for the Item Picker?