Hmm. Okay, next step. How big is your scene, what's in it, and how much system RAM do you have? VuePro has more hooks into the actual OS than Vue does, and the HyperVue Network Manager is -very- sensitive to the resources it has. It is also touchy regarding packet collision; a very large Vue or VupPro scene, or one with a poly heavy PZ-3 imported (particularly if the Poser people are using the very large, photorealistic textures) can blow things up. Have you tried not allowing VuePro to detect the Cows? Clear the HyperVue window of all the entries, shut down VuePro, restart, start a HyperVue render, and then add one and only one Cow. If it starts, wait until it is past the passing any information to the Cow and is rendering frame ), then add the next Cow (I have my garden's computers dubbed things like betsy, bossy, elsie, and rose, so it's easy to add them with their names). If you have something like cacheman, that will let you monitor how much available RAM you have from the system tray, keep an eye on that as you add Cows. Each running Cow claims a portion of system memory, so 5 Cows running can keep a noticeable portion of your memory occupied.