VBScript: Microsoft Office Project Web Access 2003

[Kate]

When we try and Open Project Professional from Project Web
Access, we get the folloing error

'VBScript: Microsoft Office Project Web Access 2003

You need Microsoft Office Project Professional 2002 or
Microsoft Office Project Professional 2003 in order to
perform this action.'

BUT it works OK if we open Project Professional and
connect via the Project Server Accounts box.

Any ideas?

Thanks

Kate