R – Visual Studio 2008, WinForms designer type conversion

Got a problem thats driving me a bit nuts here. I have a winforms project containing usercontrols, that use types from another project which is reference by add project. I have checked the references, and they are all fine, there is only one reference from the UI project to the services, and that is by adding a project reference. I can get around this problem by either deleting the resx file, or by in the designer, setting the erroring line that uses resx to null. However I ship so much time doing this everytime. Ive googled to death and checked through here with no joy. Anyone got any pointers. Error is below with stack trace

TIA

Error:

Object of type 'NewSchool.Services.Document.IDocumentDto[]' cannot be converted to type 'NewSchool.Services.Document.IDocumentDto[]'. 

Stack Trace:

at System.RuntimeType.CheckValue(Object value, Binder binder, CultureInfo culture, BindingFlags invokeAttr)
at System.Reflection.RtFieldInfo.InternalSetValue(Object obj, Object value, BindingFlags invokeAttr, Binder binder, CultureInfo culture, Boolean doVisibilityCheck, Boolean doCheckConsistency)
at System.Reflection.RtFieldInfo.InternalSetValue(Object obj, Object value, BindingFlags invokeAttr, Binder binder, CultureInfo culture, Boolean doVisibilityCheck)
at System.Runtime.Serialization.FormatterServices.SerializationSetValue(MemberInfo fi, Object target, Object value)
at System.Runtime.Serialization.ObjectManager.CompleteObject(ObjectHolder holder, Boolean bObjectFullyComplete)
at System.Runtime.Serialization.ObjectManager.DoNewlyRegisteredObjectFixups(ObjectHolder holder)
at System.Runtime.Serialization.ObjectManager.RegisterObject(Object obj, Int64 objectID, SerializationInfo info, Int64 idOfContainingObj, MemberInfo member, Int32[] arrayIndex)
at System.Runtime.Serialization.Formatters.Binary.ObjectReader.RegisterObject(Object obj, ParseRecord pr, ParseRecord objectPr, Boolean bIsString)
at System.Runtime.Serialization.Formatters.Binary.ObjectReader.ParseObjectEnd(ParseRecord pr)
at System.Runtime.Serialization.Formatters.Binary.ObjectReader.Parse(ParseRecord pr)
at System.Runtime.Serialization.Formatters.Binary.__BinaryParser.Run()
at System.Runtime.Serialization.Formatters.Binary.ObjectReader.Deserialize(HeaderHandler handler, __BinaryParser serParser, Boolean fCheck, Boolean isCrossAppDomain, IMethodCallMessage methodCallMessage)
at System.Runtime.Serialization.Formatters.Binary.BinaryFormatter.Deserialize(Stream serializationStream, HeaderHandler handler, Boolean fCheck, Boolean isCrossAppDomain, IMethodCallMessage methodCallMessage)
at System.Runtime.Serialization.Formatters.Binary.BinaryFormatter.Deserialize(Stream serializationStream)
at System.Resources.ResXDataNode.GenerateObjectFromDataNodeInfo(DataNodeInfo dataNodeInfo, ITypeResolutionService typeResolver)
at System.Resources.ResXDataNode.GetValue(ITypeResolutionService typeResolver)
at System.Resources.ResXResourceReader.ParseDataNode(XmlTextReader reader, Boolean isMetaData)
at System.Resources.ResXResourceReader.ParseXml(XmlTextReader reader)