Running the TEMU.exe utility in the /DiskOnChip area of the appsrv's file system resolves this.
If you are using OPC, then Register OPC Components checkbox should be checked. The utility will walk you through the maze of unlocking the registry. Once the registry is unlocked, this utility will register the appropriate DLLs and EXEs.
After successfully running the utility, you should cycle power and determine whether or not the problem has been corrected. If the problem persists the next possibility is a COM/DCOM problem. OSISoft made heavy use of these technologies for communication between the ECHO components. As such they would need to be consulted as to why the "Failed to connect" problem occurred.