Getting an error while reopening any lost opportunity

I have the STATECODE field in the form which I cannot remove and even I made this field as hidden and read only.

Getting this error at below.

Event code: 3005
Event message: An unhandled exception has occurred.
Event time: 2015-06-22 2:26:03 PM
Event time (UTC): 2015-06-22 6:26:03 PM
Event ID: a3c11c8a70df4ec995e3a84876beafab
Event sequence: 209548
Event occurrence: 28
Event detail code: 0
 
Application information:
    Application domain: /LM/W3SVC/1/ROOT-1-130793834371921518
    Trust level: Full
    Application Virtual Path: /
    Application Path: C:\Program Files\Microsoft Dynamics CRM\CRMWeb\
    Machine name: TPCRM
 
Process information:
    Process ID: 5024
    Process name: w3wp.exe
    Account name: TP\CRMAPPPOOLSERVICE
 
Exception information:
    Exception type: ArgumentException
    Exception message: Invalid state for this entity: opportunity: 2
Parameter name: state
   at Microsoft.Crm.Application.Platform.EntityProxy.ConvertStateToNumber(String entityName, String state)
   at Microsoft.Crm.Application.Platform.AttributeCollection.CreateOptionSetValueFromValue(String name, Object value, AttributeType attributeType, String entityLogicalName)
   at Microsoft.Crm.Application.Platform.AttributeCollection.SetEntityProperty(Entity entity, String name, String childAttributeName, Object parentProperty, AttributeMetadata attributeMetadata, Object value, IOrganizationContext context)
   at Microsoft.Crm.Application.Platform.AttributeCollection.Insert(String name, Object value, Boolean throwIfKeyExists)
   at Microsoft.Crm.Application.Platform.EntityProxy.SetData(XmlNode entityElement)
   at Microsoft.Crm.Application.Forms.AppForm.LoadFormSubmitData()
   at Microsoft.Crm.Application.Forms.EndUserForm.RetrieveParametersForEventDefault()
   at Microsoft.Crm.Application.Forms.EndUserForm.Initialize(Entity entity)
   at Microsoft.Crm.Application.Forms.CustomizableForm.Execute(Entity entity, FormDescriptor fd)
   at Microsoft.Crm.Application.Components.PageHandlers.RecordPageHandler.ConfigureFormWrapper()
   at Microsoft.Crm.Application.Components.Utility.GenericEventProcessor.RaiseEvent(String eventName)
   at Microsoft.Crm.Application.Controls.PageManager.OnPreRender(EventArgs e)
   at System.Web.UI.Control.PreRenderRecursiveInternal()
   at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)

 
 
Request information:
    Request URL: crm.power.ca/.../edit.aspx;etc=3&id={8646B8C4-49AB-E411-93F6-000C29BC959E}&pagemode=iframe&preloadcache=1434997558652&rskey=442382423
    Request path: /power/userdefined/edit.aspx
    User host address: 192.168.10.59
    User: TP\andy
    Is authenticated: True
    Authentication Type: Negotiate
    Thread account name: TP\CRMAPPPOOLSERVICE
 
Thread information:
    Thread ID: 60
    Thread account name: TP\CRMAPPPOOLSERVICE
    Is impersonating: False
    Stack trace:    at Microsoft.Crm.Application.Platform.EntityProxy.ConvertStateToNumber(String entityName, String state)
   at Microsoft.Crm.Application.Platform.AttributeCollection.CreateOptionSetValueFromValue(String name, Object value, AttributeType attributeType, String entityLogicalName)
   at Microsoft.Crm.Application.Platform.AttributeCollection.SetEntityProperty(Entity entity, String name, String childAttributeName, Object parentProperty, AttributeMetadata attributeMetadata, Object value, IOrganizationContext context)
   at Microsoft.Crm.Application.Platform.AttributeCollection.Insert(String name, Object value, Boolean throwIfKeyExists)
   at Microsoft.Crm.Application.Platform.EntityProxy.SetData(XmlNode entityElement)
   at Microsoft.Crm.Application.Forms.AppForm.LoadFormSubmitData()
   at Microsoft.Crm.Application.Forms.EndUserForm.RetrieveParametersForEventDefault()
   at Microsoft.Crm.Application.Forms.EndUserForm.Initialize(Entity entity)
   at Microsoft.Crm.Application.Forms.CustomizableForm.Execute(Entity entity, FormDescriptor fd)
   at Microsoft.Crm.Application.Components.PageHandlers.RecordPageHandler.ConfigureFormWrapper()
   at Microsoft.Crm.Application.Components.Utility.GenericEventProcessor.RaiseEvent(String eventName)
   at Microsoft.Crm.Application.Controls.PageManager.OnPreRender(EventArgs e)
   at System.Web.UI.Control.PreRenderRecursiveInternal()
   at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
 
 
Custom event details:

Thanks