showing error tkn error

Aliases.Eugenus_CTC_Utilities_SecsTestApp.HwndSource_MainWindow.MainWindow.textBoxMsgToSend.Keys("VTN:'S2F23' W\r\n<L[[5]\r\n <U4[[1] 1>/* TRID */\r\n <A[[6] "00000050">/* DSPER 6 ASCII in hhmmss or ...