Insert Method of range class failed - vb.net

Question

The following code is supposed to copy information from xlsx files(inside subfolders) and consolidate(paste) everything in a single file:
Dim xlApp, xlApp1, xlApp2 As Excel.Application
Dim xlWorkBook, xlWorkBook1, xlWorkBook2 As Excel.Workbook
Dim xlWorkSheet, xlWorkSheet1, xlWorkSheet2 As Excel.Worksheet
Dim folder, m, n As String
Dim subfolders As String()
Dim i, j, c, k, l, lastrow As Integer
Dim fec As Date
folder = My.Application.Info.DirectoryPath
ChDir(CurDir())
subfolders = IO.Directory.GetDirectories(CurDir())
xlApp = New Excel.ApplicationClass
xlApp2 = New Excel.ApplicationClass
xlApp1 = New Excel.ApplicationClass
Try
xlWorkBook = xlApp.Workbooks.Open("\\excel1.xlsx")
xlWorkSheet = xlWorkBook.Worksheets("SheetName")
xlWorkBook2 = xlApp2.Workbooks.Open("\\excel2.xlsx")
xlWorkSheet2 = xlWorkBook2.Worksheets("SheetName")
i = 2
For Each f1 In subfolders
ChDir(f1)
m = Dir("*.xlsx")
Do While m <> ""
j = 1
Do While xlWorkSheet2.Cells(j, 1).Value <> ""
If xlWorkSheet2.Cells(j, 1).Value = m Then
fec = xlWorkSheet2.Cells(j, 2).value
If fec <> File.GetLastWriteTime(CurDir() & "\" & m) Then
l = 1
n = xlWorkSheet.Cells(l, 3).value()
Do While n <> ""
If Trim(xlWorkSheet.Cells(l, 3).value) = Strings.Left(Strings.Right(m, 16), 11) Then
xlWorkBook.Activate()
xlWorkSheet.Rows(l).delete()
If Trim(xlWorkSheet.Cells(l, 3).value()) <> Strings.Left(Strings.Right(m, 16), 11) Then
n = ""
End If
Else
l = l + 1
n = xlWorkSheet.Cells(l, 3).value()
End If
Loop
xlWorkBook1 = xlApp1.Workbooks.Open(CurDir() & "\" & m)
xlWorkSheet1 = xlWorkBook1.Worksheets("Test")
xlWorkSheet1.Visible = True
xlWorkSheet1.Activate()
xlWorkSheet1.Select()
If xlWorkSheet1.FilterMode = True Then
xlWorkSheet1.ShowAllData()
End If
c = 5
Do While Trim(xlWorkSheet1.Cells(c, 4).value) <> "Entity Name"
c = c + 1
Loop
c = c + 2
If xlWorkSheet1.Cells(c, 4).value <> "" Then
xlWorkSheet2.Cells(j, 2) = File.GetLastWriteTime(CurDir() & "\" & m)
lastrow = xlWorkSheet1.Cells(65536, 3).End(Excel.XlDirection.xlUp).Row
xlWorkSheet.Cells(l, 1).Insert(Excel.XlInsertShiftDirection.xlShiftDown, xlWorkSheet1.Range("a" & c.ToString, xlWorkSheet1.Cells(lastrow, 42)).Copy())
End If
xlWorkBook1.Close()
releaseObject(xlWorkBook1)
releaseObject(xlWorkSheet1)
End If
j = j + 1000
ElseIf xlWorkSheet2.Cells(j + 1, 1).Value = "" Then
k = j + 1
xlWorkSheet2.Range("A" & k.ToString).Value = m
xlWorkSheet2.Range("B" & k.ToString).Value = "01/01/2000"
End If
j = j + 1
Loop
m = Dir()
Loop
Next
xlWorkBook2.Close()
xlWorkBook.Close()
xlApp.Quit()
xlApp2.Quit()
xlApp1.Quit()
Catch ex As Exception
...
But after this line
xlWorkSheet.Cells(l, 1).Insert(Excel.XlInsertShiftDirection.xlShiftDown, xlWorkSheet1.Range("a" & c.ToString, xlWorkSheet1.Cells(lastrow, 42)).Copy())
it fails showing the error:
System.Runtime.InteropServices.COMException(0x800A03EC): Insert Method of range class failed.
Excel files are ok, with write permissions and are local.
Any ideas?