It's not available for download. It came with Crystal Reports 7 Professional. If you can find a copy of CR 7 professional, you should be able to get the v7 CPEAUT32.dll.
The Automation Server has been discontinued in CR 9. If possible, I would recommed converting your app to use the Report Designer Component (RDC, or CRAXDRT.DLL) and the Crystal Report Viewer control (CPEAUT32.dll provided a viewer; CRAXDRT.DLL does not. Therefore, you must also add the Crystal Report Viewer Control to your project). The RDC in CR 7 should allow you to do most, if not all, of whatever you were doing with CPEAUT32.dll.