Server.CreateObject error or Library Not Registered

Possible Error Messages:

Server.CreateObject Failed
Server.CreateObject Access Error
Library not registered
There is a problem with the page you are trying to reach and it cannot be displayed

Solution - XP/2003 only:

Read this.
Ensure that the FogBugz user has full control on your FogBugz key in the registry:
HKLM/SOFTWARE/FOG CREEK/FOGBUGZ
...and the FogBugz folder itself, which is by default here:
C:\Program Files\FogBugz
If no luck yet, restart IIS.
If still no luck, proceed to next solution.

Solution - All operating systems:

Your dll's in the accessories folder may not be registered correctly. Run register.bat, which lives in that folder, and reboot.
If that doesn't fix it, you may have a permissions problem. The Windows user account that FogBugz is using may not have permissions on the dll that the COM object lives in, OR domain policy prevents it from doing a CreateObject. Make sure the FogBugz user has permissions on the FogBugz folders.
If that doesn't fix it: errors like this can also be caused if you do not have the latest version of Microsoft Windows Script. Download and install it from their web site.

Solution - If you recently ran a Dart update:

The updater may put your new Dart DLLs in:
C:\WINDOWS\SYSTEM32
or in:
C:\Documents and Settings\Administrator\Windows
In fact different Dart updates tend to put the DLLs in different folders, so if they aren't in one of the above folders may just have to do a Windows Explorer Search for "DartMail".
The FogBugz user account needs full control of these Dart DLLs. If it does not have permissions on these DLLs you will get a Server.CreateObject error. It is a Dart object that the server is trying to create.