I've been seeing mixed results with using queue manager to render across multiple machines. Sometimes, they'll come out with off or missing textures, but sometimes there will be whole figures missing. Any idea what could cause this and how to remedy it? Specifically, a lot of the texture errors I'm seeing result in all purple textures.

As a means of alerting you to missing textures, P12 assigns magenta where a texture image is missing.

So you might see this...

instead of this...

That's why you're seeing purple.

As for why the textures are missing, how are the remotes (render slaves) connected to the master? Cat5 over 10/100MB/s switch? wireless?

The most frequent cause of networked Queue issues is firewall permissions; you should verify that all of the machines have in&out permissions for Queue and FFRender64 (and Poser on the master). But since you are getting the job to the remote, I wonder if the problem is a timeout fault between master and slave. What OS are your machines, and describe your network (hardwired? wireless? Cat5? Cat7? switch speed?)