From the Beta Thread:
oh, there is, the rules said that that a beta's job isn't to check spelling and grammer, oh well, anyway I'll wait as long as I need to for my beta reader, cause it's worth it
What that means, Koneko, is that before you submit your story, it's common courtesy to proofread before you submit your work to a beta reader (which means spell checking and carefully going over your story yourself). It makes the beta's job easier, and really, a beta is there to explain the errors you keep making, not the ones you can easily spot yourself and are missing when you go through the stages of writing without a beta.