Errors and Omissions insurance coverage, covers any negligence in your business or profession. Errors and Omission insurance is the same thing as liability, or malpractice insurance for a business.
Errors and omission coverage is necessary for the agent or broker that is selling insurance to you. It protects the agency against any misleading statements either intentional or not.
E/O coverage provides for 'errors or omissions' if you run a business like accounting, law, or insurance and you provide bad advice to a client, for example.