We prove the unique solvability in the holomorphic category of a system of partial differential equations which is a higher order version of the system considered by Bielawski in his study of Ricci-flat Kähler metrics. The system is involves a higher order nonlinear equation that is singular in the variable t and is very similar to the one studied by Gérard and Tahara in the 1990s. The proof makes use of a family of majorant functions based on the ones used in Lope-Tahara and Pongérard.