Using regmon it appeared that on a machine that was working it was calling msdao15.dll
On the machine that was showing the error, which you could replicate when you opened a report created on the working machine and selected Database->Set database location and click on create new connection in the replace with part of the dialog and then select OLE DB
It was calling msdao10.dll
running regsvr32 msdao15.dll, closing and opening crystal appeared to resolve the issue.