I've already encountered this problem on people using my in-house tools on new 64 bit machines with Office 2010.
all I had to do was change lines of code like this:
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
To This:
#If VBA7 Then
Private Declare PtrSafe 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
#Else
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
#End If
You will, of course want to make sure that the library you're using is available on both machines, but so far nothing I've used has been a problem.
Note that in the old VB6, PtrSafe isn't even a valid command, so it'll appear in red as though you have a compile error, but it won't actually ever give an error because the compiler will skip the first part of the if block.
Applications using the above code compile and run perfectly on Office 2003, 2007, and 2010 32 and 64 bit.
Best Answer
The Office XP VSS addin worked fine in Excel 2007 last time I tried it (been a couple of years). It's really a VBA addin, and VBA hasn't changed much since Excel 2000 (eg, registered addins work across versions). You might need an MSDN subscription to download it, though- that's where I got it.