I assume that you are getting this error message in the federal review. If so, see the following:
Is this employer tax ID coming from the W-2? If so, do a Search (upper right) for "w-2" (lower case, without the double quotes) and jump to the results.
Choose the correct W-2 and click on Edit. Change the EIN at the top of the first screen.
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In any case, when you get the message in the review "don't fix it on this form", what they are trying to say is, "don't fix it in the review, but go back to the original form that was input, and fix it there."
In some cases, you may have to delete the form and re-add it.