Add iRule to all virtual servers without deleting existing irules

What's the name of the irule you are trying to add?

You need to replace the 'New_iRule' with your irule.

I've tried it in my lab and it works.

In your case, I see some weird lines. like "Virtual server (/Common/new=New_Irule)"

So please check your Virtual server file. I should contain only the Virtual server names