Found and interesting but not so fix. Note, even though the program emits an error after first running AudioStreamer.exe it is actually running in the Taskbar.
Right-click on the AudioStreamer icon
Select Edit config file
Change the line where has the port 9090 to 9091
-> Note the display did not show the config as when you edited it but only with #<comments>
But once I made that change and went back to Edit config file the display was correct and access the http://localhost:9090 worked! It could just be a fluke of course but worked for me.
It looks like that it is not reading the mongoose.conf file correctly when the AudioStreamer.exe starts up initially.