I`m not an insurance agent, but have experience in securing insurance for businesses. Based on what I read in your profile, it sounds like you should also have professional liability coverage to include Errors & Omissions and Directors & Officers.
Given that you provide training to the people you hire and the subcontracting you provide to other companies, you are opening yourselve up to all types of problems without these coverages.
Just my two cents...
It is a big heavy to prescribe D&O and E&O without knowing more about the business. Nevertheless it is a good sugestion if the business is a corporation that provides professional services. I doubt a cargo firm is going to need e&o, but not out of the question, depending on what they do. D&O is not required, needed, nor would be underwitten for a sole propriership. This is why it is important to have the right broker instead of someone who is just going to slap on the lowest price. Providing the lowest price is the easiest thing a broker can do, the biggest reason why a broker would sell on price is because they are not knowledgeable about the products they are selling as wells as wanting to close the deal as fast as they can.