If you’re thinking of uninstalling/reinstalling Microsoft Speech Server on Windows Vista then this post might prove helpful.
It seems that Speech Server Setup doesn’t do such a good job uninstalling itself from Vista. And when you reinstall the server it fails to properly configure IIS. Namely it has a number of problems dealing with the *.speax exemption. This results it 404.2 and 500 errors being returned by IIS when you attempt to launch a Speech Server application.
The workaround I’ve found for this issue requires manually mapping the handler for *.speax in your application’s web.config. Adding the following to the <system.webServer> section will map IIS to the correct handler:
<remove name="MSSCustomMap" />
<add name="MSSCustomMap" path="*.speax" verb="*" modules="IsapiModule" scriptProcessor="C:WindowsMicrosoft.NETFrameworkv2.0.50727aspnet_isapi.dll" resourceType="Unspecified" requireAccess="Script" responseBufferLimit="0" />