Some of the error messages are cryptic. I do have plans to write a tutorial about interpreting the messages, but have not yet gotten to it.
Post your error messages and let's see if we can help.
BTW, many of the errors reported simply mean that the page's code does not meet the specification set by the DOCTYPE tag. It doesn't necessarily mean that the page is broken.
"It's inexcusable for scientists to torture animals; let them make their experiments on journalists and politicians." -Henrik Ibsen