If you modify the number of tasks used by the ice model, the model may stop with this error written to the log file:
'ERROR: NX must divide evenly into grid,100,8'
The number of MPI processors used by the ice model must divide evenly into the grid dimensions. For example, running the ice model with 8 tasks on the gx3v5 grid will result in an error, since 8 does not divide evenly into the 100 longitude points. To fix this error, change the value of $NTASKS for the uncoupled ice model in the main script. In this case, a value of 4 would work, and the task geometry would also have to be changed.