If you facing this error...
if you save or read a column using splistitem["Created By"] or splistitem[internalname]...
You get this error...
Exception Unhandled exception caught during execution of Microsoft.SharePoint.Portal.PageBase::ErrorHandler(). Exception information: Exception information: System.ArgumentException: Value does not fall within the expected range. at Microsoft.SharePoint.SPFieldMap.GetColumnNumber(String strFieldName, Boolean bThrow) at Microsoft.SharePoint.SPListItemCollection.GetColumnNumber(String groupName, Boolean bThrowException) at Microsoft.SharePoint.SPListItemCollection.GetRawValue(String fieldname, Int32 iIndex, Boolean bThrow) at Microsoft.SharePoint.SPListItem.GetValue(SPField fld, Int32 columnNumber, Boolean bRaw, Boolean bThrowException) at Microsoft.SharePoint.SPListItem.GetValue(String strName, Boolean bThrowException) at Microsoft.SharePoint.SPListItem.get_Item(String fieldNa...
Your list has a too much columns (Lookup, Person/Group, or workflow status fields)
You need to increase your "List View Lookup Threshold"
Go to Application Management --> Manage Web Applications --> select your application --> General Setting --> Resource Throttling --> List View Lookup Threshold --> Put a number more than number of your list columns. maybe 30, 40, or 50.
and Save it.
Now It should be working!