It could be the graphical client - two 3D apps at the same time might have an impact.
For the console client, you'd just need to copy fah504-console.exe into a new directory and then run the setup there. I wouldn't suggest importing settings as will have to adjust them anyway. Try it with lower settings (no to >5MB project, no advance projects, 80% cpu use, idle priority and a different machine ID than the other two folding clients) and see how that works (and with the graphic client off!).
Let us know how it goes!