If your business provides advice or consultancy services in a professional capacity, you will be considered an expert by your clients. In today's increasingly litigious culture, clients will not hesitate to sue you if they believe that they have suffered a loss as a result of sub standard service. This is where Professional Indemnity insurance can help protect you.
General background information regarding this type of insurance can be found on our cherry picked insurance site.
You may also wish to consider Directors and Officers insurance.