Hello, there's no reason to have 85% rejected, of course it isn't normal and there must be something specific in your config. Please send me your miner settings to email together with your pool login.
For example yesterday one guy contacted me because he had very high rejected ratio. Then we found that he was using wrong domain on his side for some miners (api1.bitcoin.cz instead api.bitcoin.cz or api2. bitcoin.cz). So there might be some stupid mistake, too.