Problem Trimming a Frame

Good afternoon everyone,
I am designing a canopy and I find very difficult to find a solution to this problem.
I already defined the shape of the canopy an

Question TRIMMING (42.5 KB)
d also the frame, but while cutting it I get some errors and I cannot figure out why.
Is there someone who can help me to get a clean cutting shape definition?

Thank you very much ^^

Like this?

Question TRIMMING (45.0 KB)

Yes! that’s perfect, thank you very much Kim!