I would use the ShellExecute API. This way the access program can be used on any computer with arcview installed without using the exact path to arcview.exe.
Private Declare Function ShellExecute 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
private sub button_click()
Private Const SW_SHOWNORMAL = 1
ShellExecute Me.hwnd, vbNullString, "any_apr_file.apr", vbNullString, "C:\", SW_SHOWNORMAL
end sub