Getting the ASIO4all driver working correctly on windows can be a challenge. Scattered notes from other singers follow; drop me a line if you have other ideas/stories/suggestions.
I was unable to connect to any jamulus servers (stuck on "Trying to Connect").
In my system settings (Control Panel) I went to "change system sounds"
I selected my default speaker/headphone device (Realtek(R) Audio for my laptop)
Clicking into the device properties there's an "Advanced" tab, the default setting on the drop down is 24 bit (48000 Hz)
I selected 16 bit, 48000 Hz, and all of a sudden I could connect to the Philly Jamulus server and select ASIO4all as my device in the Jamulus settings.
When setting up the "device" in Jamuls, look for something that resembles "in: Realtec-Microphone/out :Realtec- Output" or "in: ASIO4all/ out: ASIO4all." Our friends a SBCC have found issues when selecting "System Default" so don’t use that setting.