Copy Files to computers on a Network using a Windows Service

Aim:
   Be able to copy files to different computers(on a network) using a Windows Service

Project:
  Using a Windows Service, it calls a frmService.vb (VB.NET Windows Form) that contains a function which performs actions such as downloading files from FTP to my computer and deploying files to different computers on a network (to a shared folder).

Problem:
  Downloading a file from FTP is OK, but, copying (deploying) the files to computers on a network raises an error saying: ...

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System.IO.IOException: The network path was not found
 at System.IO._Error.WinIOError(Int32 errorCode, String str)
 at System.IO.File.InternaleCopy(String sourceFileName, String destFileName, Boolean Overwrite)
 at System.IO.File.Copy(String sourceFileName, String destFileName, Boolean OverWrite)
 at v2k_functions.filecopy(String srcFile, String destFile)
 ===============================================================

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System.UnauthorizedAccessException: Access to the path "\\NAME\A\B\abc.mde" is denied.
  System.IO.IOException: The network path was not found
 at System.IO._Error.WinIOError(Int32 errorCode, String str)
 at System.IO.File.InternaleCopy(String sourceFileName, String destFileName, Boolean Overwrite)
 at System.IO.File.Copy(String sourceFileName, String destFileName, Boolean OverWrite)
 at v2k_functions.filecopy(String srcFile, String destFile)
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Here is the Function that performs the copying of a file to computers:  

 Function filecopy(ByVal srcfile As String, ByVal destfile As String)
        Try
            Dim x As IO.File
            x.Copy(srcfile, destfile, True)
            Return True
        Catch e1 As Exception
            MsgBox(e1.ToString)
            Return False
        End Try
    End Function

For x = 0 to arrNames.Length - 1

    Dim dest1 As String    
    dest1 = "\A\B\abc.mde"
         
    If filecopy("C:\V2KSUS\Visual 2000 Report.mde", "\\" + arrNames(x) + dest1) = False Then
       ' If successful then put them in an array
   Else
       ' Count how many computers that has been copied successfully
    End If

Next


Possible Cause:
   - Since I installed the Windows Service using a LOCAL SYTEM account, I might have no access to computers in the network.

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>> If I install the service using a NETWORK SERVICE or LOCAL SERVICE account, it does not work.

      Possible Cause:
   - The frmService.vb has MessageBox and ProgressBar, it does not allow any MessageBox or any interface. Using the LOCAL SYSTEM allows to interact with the desktop.

  >> On the other hand, I also tried executing the form without using a Windows Service and it works perfectly.