In this article, we prove that a space of cusp forms of weight 2 with level N and real character chi has dimension 1 if and only if chi is trivial and N is in {11, 14, 15, 17, 19, 20, 21, 24, 27, 32, 36, 49}, and derive bases for spaces of cusp forms of weight 2 with trivial character and N is an element of {17, 19, 21, 49}. As applications, we provide formulas for the number of representations of integers by 4-dimensional strongly N-modular lattices for N in {11, 14, 15, 17, 19, 20, 21, 24, 27, 32, 36}.