I have a database with tblMain and a related tblLink, represented in my
application by a form/subform.  The subform fsubLink is for adding links to
files that are relevant to the main form's record.  The trouble comes when I
attempt to view the links using Application.FollowHyperlink.  Registered
non-office files such as pdf open OK.  Excel opens, but with a "Reference is
not valid" message, which occurs even when the file is a blank workbook.
Powerpoint opens with no problem (links to PowerPoint files are unlikely,
but I tested anyhow).  The biggest problem comes with Word files, which open
very, very slowly, with much flickering of the screen if I attempt to do
anything (such as navigate to another record) other than wait.  The
flickering seems to be an error message about the system being busy, so
whatever I requested (e.g. going to another record) will have to wait.  The
problem only seems to occur with a document on a network UNC path.  Mapped
drive letters do not present a problem, nor do files on my local hard drive.

I have searched around for a while and learned that a ShellExecute API (like
the one at the MVP site) is a good way to go about opening files, but before
I go about trying to implement that code, is it a worthwhile course to take?
I have posted the code below for easy reference.  The trouble for me is that
the posted code, along with its explanation, leave unanswered questions that
I would attempt to solve by trial and error.  For instance, the web page
says that I need to:
"Pass the filename to fHandleFile function."
However, I am unclear on how to do that.  I expect the full UNC path would
need to be passed to fHandleFile.  The link is stored in a hyperlink field
(to which a text box is bound), which is populated via the standard Windows
hyperlink dialog.  Would I pass the text box name (or the name of the
hyperlink field) to fHandleFile?

Or am I missing something simple like a library reference that would enable
FollowHyperlink to work in the cases that are causing problems?  Or is there
another approach I have not mentioned that works?

Here is the code from the Access MVP web site:

'************ Code Start **********
' This code was originally written by Dev Ashish.
' It is not to be altered or distributed,
' except as part of an application.
' You are free to use it in any application,
' provided the copyright notice is left unchanged.
'
' Code Courtesy of
' Dev Ashish
'
Private Declare Function apiShellExecute Lib "shell32.dll" _
   Alias "ShellExecuteA" _
   (ByVal hwnd As Long, _
   ByVal lpOperation As String, _
   ByVal lpFile As String, _
   ByVal lpParameters As String, _
   ByVal lpDirectory As String, _
   ByVal nShowCmd As Long) _
   As Long

'***App Window Constants***
Public Const WIN_NORMAL = 1         'Open Normal
Public Const WIN_MAX = 3            'Open Maximized
Public Const WIN_MIN = 2            'Open Minimized

'***Error Codes***
Private Const ERROR_SUCCESS = 32&
Private Const ERROR_NO_ASSOC = 31&
Private Const ERROR_OUT_OF_MEM = 0&
Private Const ERROR_FILE_NOT_FOUND = 2&
Private Const ERROR_PATH_NOT_FOUND = 3&
Private Const ERROR_BAD_FORMAT = 11&

'***************Usage Examples***********************
'Open a folder:     ?fHandleFile("C:\TEMP\",WIN_NORMAL)
'Call Email app:    ?fHandleFile("mailto:dash10@hotmail.com",WIN_NORMAL)
'Open URL:          ?fHandleFile("http://home.att.net/~dashish", WIN_NORMAL)
'Handle Unknown extensions (call Open With Dialog):
'                   ?fHandleFile("C:\TEMP\TestThis",Win_Normal)
'Start Access instance:
'                   ?fHandleFile("I:\mdbs\CodeNStuff.mdb", Win_NORMAL)
'****************************************************

Function fHandleFile(stFile As String, lShowHow As Long)
Dim lRet As Long, varTaskID As Variant
Dim stRet As String
   'First try ShellExecute
   lRet = apiShellExecute(hWndAccessApp, vbNullString, _
           stFile, vbNullString, vbNullString, lShowHow)

   If lRet > ERROR_SUCCESS Then
       stRet = vbNullString
       lRet = -1
   Else
       Select Case lRet
           Case ERROR_NO_ASSOC:
               'Try the OpenWith dialog
               varTaskID = Shell("rundll32.exe shell32.dll,OpenAs_RunDLL "
_
                       & stFile, WIN_NORMAL)
               lRet = (varTaskID <> 0)
           Case ERROR_OUT_OF_MEM:
               stRet = "Error: Out of Memory/Resources. Couldn't Execute!"
           Case ERROR_FILE_NOT_FOUND:
               stRet = "Error: File not found.  Couldn't Execute!"
           Case ERROR_PATH_NOT_FOUND:
               stRet = "Error: Path not found. Couldn't Execute!"
           Case ERROR_BAD_FORMAT:
               stRet = "Error:  Bad File Format. Couldn't Execute!"
           Case Else:
       End Select
   End If
   fHandleFile = lRet & _
               IIf(stRet = "", vbNullString, ", " & stRet)
End Function
'************ Code End **********