I have only been using Plexus for a few weeks now and I have come across a game ending issue. Whenever I increase the point size past like 7 it completely crashes After effects. Is there anyway to solve this?
In some brief experimentation with Plexus primitives I have found that the point size maxes out at 1000, but never crashes AE. I'm on CS6 on a Mac, so your issue may be one of incompatibilities between Plexus and your version of AE.
Have you tried contacting Rowbye Software support? If there is a compatibility issue hopefully they are aware of it, or can at least suggest ways to troubleshoot your system.