Difficulties with #985 Peristaltic Pump Model

Hi All

(bear with me; I'm new)

Working my way through the peristaltic pump tutorial and all has been a-okay thus far but once I get to the plot of the total volume (bottom of pg. 14) when I try to evaluate the surface integration for the volume it says no solution exists. I am sure that all the boundary conditions are properly defined. Hoping someone has had a similar issue..

Any ideas?

Thanks,

Alexis