We LOVED Beautiful Oops!! What a brilliant concept... creating art out of slip-ups. Definitely recommend that book.
My DD11 went through the perfectionism angst (I could write a book, lol). She's much better now.
Two things jump to mind...
a) praise for effort, and NOT results
b) don't smother with praise, because then you lose credibility in the child's eyes (they have wonderful BS detectors)
I like the way you pointed out that parents sometimes make mistakes too - next time you catch yourself in a mistake, point it out to her. Model the behaviour you want to see - as in, forgive yourself, and continue on.
Also, teach her that mistakes are a part of learning. If everything is super easy and perfectionism is attainable, it's not worth her valuable learning time.
The best thing you can do at this point is challenge her and put her in situations where she'll make errors, and stay calm and non-reactive when she melts down. She just needs to get used to challenge, and in doing so, develop emotional resiliency.
