We encountered several problems with the MPI version of VASP.4 on the CRAY J90. First MPI_double_precision (MPI_double_complex) must be changed to MPI_real (MPI_complex). Second the reading of the INCAR file must be serialized (i.e. only one node can do the reading at a time). Defining CRAY_MPP in the makefile fixes these problems. But we are not yet sure whether this flag is required on all CRAY MPP machines or not.