programmatically register Word 2007 addin in vb6 on Vista

[moonflower]

I have a Word 2007 addin (myRibbon.dll) that I need to programmatically
register in a vb6 application. At
http://archive.devx.com/vb/free/articles/vb2themax/10tips/fb0201-6.asp I
found the example that I used to code the followings instruction:

Public Declare Function RegisterDLL1 Lib "myribbon.dll" Alias
"DllRegisterServer" () As Long
Dim ret As Long

ChDrive "I:\"
ChDir "I:\NewJJIS1DLLs\"
ret = RegisterDLL1()
If Err <> 0 Then
MsgBox "Unable to find myribbon.dll"
ElseIf ret <> ERROR_SUCCESS Then
MsgBox "Registration failed"
End If

When I execute this code ret contains –2147467259. Can you tell me why I am
getting this error and how I can prevent it from occurring?