Yet another frequently asked question. When using the BizTalk 2004 Administration Console, isolated hosts always report "Status unavailable" (see below).
Isolated hosts primarily host adapters that must run outside of the normal BizTalk Server runtime process. For example, you use isolated hosts to host adapters for external processes such as ISAPI extensions and ASP.NET.
The status of an isolated host is always Status Unavailable. BizTalk Server does not access the status information for external processes.