To understand more about the error being faced inside the Invoke Code, try using Try Catch Block inside it like the below Updated Code.
We would require to handle the Exceptions inside Invoke Code Activity to be able to understand where/what was the exact error.
Dim xlApp As Microsoft.Office.Interop.Excel.Application
Dim wb As Microsoft.Office.Interop.Excel.Workbook
xlApp = New Microsoft.Office.Interop.Excel.Application
wb = xlApp.Workbooks.Open(in_FilePath)
xlApp.DisplayAlerts = False
xlApp.DisplayAlerts = True
Catch e As Exception
Console.WriteLine(e.Message+" at "+e.Source)
Let us know if the above gives out a precise error that we can point to and work on fixing this error.
You should Check the Output Panel for the Error message that is being logged.
Also, Do note that, if the Excel has only one sheet present, the Delete operation will give out an Error, as there should be atleast one Sheet present in the Excel.