System.Reflection.TargetInvocationException in Linq

I want to get Count as Below.
but it occured error
can you help me?

  1. count of school > pc> level1

  2. count of school > pc> level2

  3. count of school > pc> level3

  4. count of school > pc> level4

  5. count of school > notebook> level1

  6. count of school > notebook> level2

  7. count of school > notebook> level3

  8. count of school > notebook> level4 (9.6 KB)

[error detail]

Source: Invoke Code

Message: Exception has been thrown by the target of an invocation.

Exception Type: System.Reflection.TargetInvocationException

An ExceptionDetail, likely created by IncludeExceptionDetailInFaults=true, whose value is:
System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ----> System.ArgumentException: Column ‘Column0’ does not belong to table .
at System.Data.DataRow.GetDataColumn(String columnName)
at System.Data.DataRow.get_Item(String columnName)
at System.Data.DataRowExtensions.Field[T](DataRow row, String columnName)
at UiPathCodeRunner_5619e9ab1baa4687ab903ec88a3afbc5._Lambda$__1(DataRow DT)
at System.Linq.Enumerable.WhereEnumerableIterator1.MoveNext() at System.Linq.Enumerable.WhereEnumerableIterator1.MoveNext()
at System.Linq.Enumerable.Count[TSource](IEnumerable`1 source)
at UiPathCodeRunner_5619e9ab1baa4687ab903ec88a3afbc5.Run(DataTable DT1, Int32 ArrCount1)
— End of inner ExceptionDetail stack trace —
at System.RuntimeMethodHandle.InvokeMethod(Object target, Object arguments, Signature sig, Boolean constructor)
at System.Reflection.RuntimeMethodInfo.UnsafeInvokeInternal(Object obj, Object parameters, Object arguments)
at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object parameters, CultureInfo culture)
at System.RuntimeType.InvokeMember(String name, BindingFlags bindingFlags, Binder binder, Object target, Object providedArgs, ParameterModifier modifiers, CultureInfo culture, String namedParams)
at UiPath.Core.Activities.Workflow.CompilerRunner.Run(Object args)
at UiPath.Core.Activities.InvokeCode.Execute(CodeActivityContext context)
at System.Activities.CodeActivity.InternalExecute(ActivityInstance instance, ActivityExecutor executor, BookmarkManager bookmarkManager)
at System.Activities.ActivityInstance.Execute(ActivityExecutor executor, BookmarkManager bookmarkManager)
at System.Activities.Runtime.ActivityExecutor.ExecuteActivityWorkItem.ExecuteBody(ActivityExecutor executor, BookmarkManager bookmarkManager, Location resultLocation)

Hi @SunnyK

Could you check these two topics with a solution to that error message?

@SunnyK Can you try this