Errors with Microsoft.Interop.Excel on all Workstations except the one the application was written on.

Private Sub cmdOK_Click_1(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdOK.Click 'The main event: connects to Timesheet Templates and fills in all of the info
        Dim i = 0, x = 0
        Dim strTimeSheet, strWorkSheetName, filename, fancy, strCell1, strCell2 As String
        Dim sbExcelData As System.Text.StringBuilder
        Dim aExcel As New Excel.Application
        Dim aWorkbook As Excel.Workbook
        Dim aWorkSheet As Excel.Worksheet
        Dim aWorkRange As Excel.Range
        Dim aProcesses() As Process = Process.GetProcesses
        Dim checkDate As Date = calTimesheet.SelectionStart.Date
        Dim endcheck As Date = checkDate.AddDays(14).Date
 
        Me.Hide()
        aExcel.Application.SheetsInNewWorkbook = 1
 
        Select Case trigger
            Case 1
                path1 = "C:\Documents and Settings\" & username & "\TimeSheet\Templates\980Hourly.xls"
                path2 = "C:\Documents and Settings\" & username & "\Timesheet\980Hourly.xls"
                strTimeSheet = "980Hourly.xls"
                strWorkSheetName = "980Hourly"
            Case 2
                path1 = "C:\Documents and Settings\" & username & "\TimeSheet\Templates\Salary.xls"
                path2 = "C:\Documents and Settings\" & username & "\Timesheet\Salary.xls"
                strTimeSheet = "Salary.xls"
                strWorkSheetName = "Salaried"
            Case 3
                path1 = "C:\Documents and Settings\" & username & "\TimeSheet\Templates\Standard.xls"
                path2 = "C:\Documents and Settings\" & username & "\Timesheet\Standard.xls"
                strTimeSheet = "Standard.xls"
                strWorkSheetName = "Standard"
        End Select
 
        Try
            ' Ensure that the target does not exist.
            If System.IO.File.Exists(path2) Then
                System.IO.File.Delete(path2)
            End If
            ' Copy the file.
            'System.IO.File.Copy(path1, path2)
        Catch
            Call killprocesses()
        End Try
 
        aExcel.Visible = False
 
        Try
            aWorkbook = aExcel.Workbooks.Open(path1)
            aWorkSheet = CType(aWorkbook.Sheets(strWorkSheetName), Microsoft.Office.Interop.Excel.Worksheet)
            aWorkSheet.Activate()
        Catch ex As Exception
            MsgBox(ex.Message, MsgBoxStyle.Critical, "Error!")
        End Try
 
        'The Following will fill the information in the timesheet for the User
 
        Select Case trigger
            Case 1 '9/80 Hourly
                If Switch = False Then
                    aWorkSheet.Cells(41, 1) = txtEmpNum.Text
                    aWorkSheet.Cells(43, 4) = txtName.Text
                End If
 
                Do Until checkDate.Date = endcheck.Date 'This will cycle through each date starting from the Calendar objects Start Selection to the End Selection
                    Do Until x = 12 'Will look through all 12 of the Holidays and see if one of the days in checkDate is a Holiday
                        If checkDate.Date = arDate(x).Date Then 'If it is then it will Add "Holiday" to the cell above the date in the spreadsheet and gray out the day
                            doit(checkDate)
                            aWorkSheet.Cells(intRow, intCol) = "Holiday"
                            aWorkSheet.Cells(intRow, intCol).Font.Bold = True
                            aWorkSheet.Cells(intRow, intCol).Font.Underline = True
                            aWorkSheet.Cells(intRow, intCol).Font.Size = 10
                            aWorkSheet.Cells(intRow, intCol).HorizontalAlignment = 3
                            strCell1 = cellz & CStr(intRow + 3)
                            strCell2 = cellz & CStr(intRow + 10)
                            aWorkSheet.Range(strCell1, strCell2).Interior.Color = RGB(192, 192, 192)
                            Exit Do
                        Else
                            cellz = ""
                        End If
                        x = x + 1
                    Loop
                    x = 0
                    checkDate = checkDate.AddDays(1)
                Loop
 
                aWorkSheet.Cells(5, 2) = calTimesheet.SelectionStart.Date
                aWorkSheet.Cells(43, 11) = Date.Today.Now.Date
            Case 2 'Salary
                If Switch = False Then
                    aWorkSheet.Cells(35, 1) = txtEmpNum.Text
                    aWorkSheet.Cells(37, 3) = txtName.Text
                    aWorkSheet.Cells(7, 2) = "X"
                    aWorkSheet.Cells.Range("E7", "H7").Value = "X"
                    aWorkSheet.Cells.Range("E17", "I17").Value = "X"
                End If
 
                aWorkSheet.Cells(5, 2) = calTimesheet.SelectionStart
                aWorkSheet.Cells(37, 10) = Date.Today.Now.Date
            Case 3 'Standard
                If Switch = False Then
                    aWorkSheet.Cells(40, 1) = txtEmpNum.Text
                    aWorkSheet.Cells(40, 7) = txtName.Text
                End If
 
                aWorkSheet.Cells(5, 2) = calTimesheet.SelectionStart.AddDays(2)
        End Select
 
        filename = "C:\Documents and Settings\" & username & "\Timesheet\" & strTimeSheet
        aExcel.ActiveWorkbook.SaveAs(filename)
        aExcel.ActiveWorkbook.Close()
 
        Call Settings()
        System.Diagnostics.Process.Start("Excel.EXE", filename)
        End
    End Sub