RP samples require good structure of your sentences, correct grammar, correct punctuation, and such.
Now, really, it just means you need to practice your skills a little more and in no time, you'll be literate, or at least close. I remember having barely any literacy and by watching others, I caught on quickly and learned.
Now, if your sample is not good enough, tough luck. It's really not a problem, it's just a part of rp to have a bad sample and not get accepted. No worries, you'll learn to to get more literate and eventually provide a good sample.
I'm sorry if you think they're too tough. :c Really, I do. But sometimes, Rps require to have their members literate so the roleplay provides satisfaction and fun. Maybe you could join a roleplay that doesn't require a sample. Don't let it bother you, and I think this is in the wrong section. It should be 'Game Discussion' I think.