In a dispute over insurance coverage pursuant to an “ongoing sub-contract agreement” under which a subcontractor was required to obtain insurance covering the contractor and other parties as additional insureds and had a duty to notify the insurer of any possible claims, the contractor and an additional insured were entitled to coverage for the injury of an employee of the named insured, despite the breach of the notice requirement by the subcontractor, the named insured, since the additional insureds complied with their dutyto give notice and coverage for the additional insureds was not contingent on the named insured’s compliance with the notice provision; furthermore, the party added by the contractor to the project that resulted in the injury at issue was an additional insured, even though the party’s name did not appear in the ongoing agreement, because the agreement, the work order for the project, and the certificate of insurance satisfied the requirement of a written contract.