Need help about strange error

Hi,

Recently, I wrote a program in Outlook to be able to synchronize the
customer from the main database. The customer are stocked in a public
folder.
Everything was wonderfull but I try to send this code to VB 6.0 and when I
try to access a public folder with this code it crash:

Const strDossierClient As String =
"000000001A447390AA6611CD9BC800AA002FC45A030042C9A0501333D711B8FE0008C7337CC
E000000008D1A0000"
........

Set objApplication = New outlook.Application
Set objNameSpace = objApplication.GetNamespace("MAPI")
Set objFolder = objNameSpace.GetFolderFromID(strDossierClient)
.........

And I get this error when the line Set objFolder =
objNameSpace.GetFolderFromID(strDossierClient) is executed :

Description: The messaging interface has returned an unknown error. If the
problem persists, restart Outlook.
Error number: -2079063551

I'll get this error only when my outlook is not open. In the other case the
synch is working well!!

Someone can help me?

Thank you

Stephane