Microsoft Knowledge Base Article 306518 contains the following summary:

This article lists various 80004005 error messages, the most frequent causes of the error messages, and troubleshooting steps to resolve them. The 80004005 error is received by Microsoft Data Access Components (MDAC) in Active Server Pages, including Microsoft ActiveX Data Objects (ADO), OLE DB, and the Remote Data Service (RDS). Although this article assumes that you are using ADO within an Active Server Pages (ASP) page, the causes and many of the troubleshooting steps are applicable to any environment in which you use ODBC for data access.