Software Deployment

ALmost always, these errors are due to either the account being used having insufficient permissions to write to the registry or, more likely, that the DLL is dependent on other files which are absent. Use Dependency Walker to identify all the files on which the DLL in question is dependent.

Less common are attempts to register files before they've been installed, probably by sequencing a Custom Action incorrectly. In that case, abandon using the CA (the lazy way to register DLLs) and use your auhtoring tool's utility to extract the COM information to a .REG file, import that and have the tool populate the advertising tables.