Exception Details: System.Runtime.InteropServices.COMException: Class

Hi, all:

My web application does TTS using Microsoft Speek SDK 5.1. It works
very well on 4 machines except one machine. all machine's OS is
windows2003 and iis6.0. but on this particular machine, I got the
following error:


Class not registered (Exception from HRESULT: 0x80040154
(REGDB_E_CLASSNOTREG))
Description: An unhandled exception occurred during the execution of
the current web request. Please review the stack trace for more
information about the error and where it originated in the code.

Exception Details: System.Runtime.InteropServices.COMException: Class
not registered (Exception from HRESULT: 0x80040154
(REGDB_E_CLASSNOTREG))

Source Error:

An unhandled exception was generated during the execution of the
current web request. Information regarding the origin and location of
the exception can be identified using the exception stack trace
below.

Stack Trace:


[COMException (0x80040154): Class not registered (Exception from
HRESULT: 0x80040154 (REGDB_E_CLASSNOTREG))]
SpeechLib.SpVoiceClass.Speak(String Text, SpeechVoiceSpeakFlags
Flags) +0

Search it on internet, did not find anything useful. All they say is
the actual dll (SAPI.dll in this case) does not registered, but I
search regedit, it is there.

I reinstalled SpeechSDK5.1 but still got the same error. I also
compiled the simpleTTS CSharp version (comes with SpeechSDK5.1
installation, and put it on the problematic machine, it works fine,
which means the dll is registered I assume.


I have no clue for what else I should check. Anybody please give
advices?

thanks in advance
-rockdale