Run Time Error 1004 and I can't Find the Issue

I am trying to search for a name in a very long list and record the sick, vacation, and personal hours that are listed for each employee. Everytime I try to run this code I get a Run Time 1004 Application or Object not Defined error. Where am I going wrong?

I keep encountering the error on the first line of the Do Until Loop.

Sub PayrollHours()
    Dim EmplName As String
    Dim FindCell As Range
    Dim SickCell As Range
    Dim PersonalCell As Range
    Dim VacationCell As Range
    Dim HoursLeft As Range
    Dim NameCell As Range
    Dim OffRow As Integer
    
    OffRow = 1
        
    Worksheets("Total Hours Calculator").Range("C8, D8, E8, F8, G8").ClearContents

    Set NameCell = ThisWorkbook.Worksheets("Total Hours Calculator").Range("C8")
    Set SickCell = ThisWorkbook.Worksheets("Total Hours Calculator").Range("D8")
    Set PersonalCell = ThisWorkbook.Worksheets("Total Hours Calculator").Range("E8")
    Set VacationCell = ThisWorkbook.Worksheets("Total Hours Calculator").Range("F8")
    Set HoursLeft = ThisWorkbook.Worksheets("Total Hours Calculator").Range("G8")
    
    EmplName = InputBox("Please Enter the Employee's Name")
        
    ThisWorkbook.Worksheets("Payroll_Detail").Range("A:A").Select
    Set FindCell = Selection.Find(EmplName, LookIn:=xlValues, LookAt:=xlPart, SearchOrder:=xlByRows, SearchDirection:=xlNext, MatchCase:=False)
    
    If FindCell Is Nothing Then
    MsgBox "Name Not Found"
    Else: NameCell = FindCell.Value
    End If
        
    With Workbooks("payroll hour calculator").Worksheets("Payroll_Detail")
    
    Do Until FindCell.Offset(OffRow, 0).Value = ""
        If FindCell.Offset(OffRow, 0).Value = "Sick" Then
            SickCell = SickCell + FindCell.Offset(OffRow, 1).Value
        ElseIf FindCell.Offset(OffRow, 0).Value = "Personal" Then
            PersonalCell = PersonalCell + FindCell.Offset(OffRow, 1).Value
        ElseIf FindCell.Offset(OffRow, 0).Value = "Vacation" Then
            VacationCell = VacationCell + FindCell.Offset(OffRow, 1).Value
        End If
        OffRow = OffRow + 1
    Loop
    End With
    
    HoursLeft = 152 - (SickCell + PersonalCell + VacationCell)
    
End Sub