E_FAIL on DllRegisterServer in Win2008 R2 x64

We are getting the error below calling c:\windows\syswow64\regsvr32.exe on Windows Server 2008 R2 x64. This used to work fine on Win2003 x64, with our 32-bit COM DLLs, so we could use them from 32-bit processes.

It's happening on a开发者_运维知识库ll ATL COM DLLs of ours, and doesn't seem related to DLL load dependencies. (Tried using depends.exe, and nothing was apparent.)

> The module ".\foo_com.dll" was loaded but the call to DllRegisterServer failed with error code 0x80070005. <<<

These DLLs were built with VS2008, ATL (UNICODE).

Any ideas?

Thanks, Kirk

If UAC is on, are you launching this from a cmd shell with admin privileges active ?