There are no mistakes.
"whereon" is a single word, not two words with a missing space. This is an accurate quotation from Exodus 3:5 in the English translation of the Bible known as the "King James version." It was completed in 1611. This translation was officially authorized by the Church of England and has become a cultural monument in the English-speaking world. However, the language has changed since 1611. Many native English speakers find the English of Shakespeare and the Bible to be hard to understand because of its use of style, grammar, and words that are no longer used, or very rarely used.
If you are studying the Bible as a monument of English literature, the King James version is probably the appropriate translation to use. If you want an English version of the Bible that is easy to understand, then a modern translation would be more appropriate. A very popular modern translation is the New International Version. A friend of mine who cares about such things says that he thinks the New English Translation or "NET Bible" is the most reliably accurate translation.
Your passage is given in the NIV as:
“Do not come any closer,” God said. “Take off your sandals, for the place where you are standing is holy ground.”
In the NET Bible:
God said, “Do not approach any closer! Take your sandals off your feet, for the place where you are standing is holy ground.”