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Try this;
That error means "Class not registered". It usually means that the dll you are trying to register does not have all its supporting dll's present, or that you don't have sufficient permissions. If you have another Admin account, try signing into that and running regsvr32. Whether you have the credentials depends where the dll was created. This is from MS, but it is still possible to get around the restrictions by using your machine's Admin account:
"DLLRegisterServer in failed.
Return Code was: 0x80004005
This error message occurs when you try to register the DLL on a
computer other than the one on which it was created.
CAUSE
The WebClass run-time files must be installed to register a WebClass DLL. This error occurs if you try to register the DLL on a computer that does not have the WebClass run-time files installed and registered.
RESOLUTION
To resolve this problem, use one of the following methods:
The best way to deploy a WebClass is to use the Package and Deployment Wizard. The Package and Deployment Wizard packages the dependent WebClass run-time DLLs when your WebClass is deployed.
Try registering atl.dll to see what message you get.
If there is a missing file, reinstalling defrag with dfrg.inf may solve he problem. That would also replace missing or damaged registry entries. But a full system scan with sfc /scannow may also be required since there are very many dependencies and supporting files for defrag. If you can't find dfrg.inf, be sure you have hidden files unhidden in Folder Options.
With thanks to Elvandil from Tech Support Guy
http://support.microsoft.com/gp/assistsupport