matlabpool success/failure depending on number of workers

Linux cluster with two users - first user has created a matlabpool with 96 workers. second user should be able to create a matlabpool with 48 workers, but can't get more than 10. Any thoughts on possible causes and/or how to troubleshoot would be helpful.

Matlab version: R2013a

Configuration: 18 nodes, 144 workers (8 per), all tests passed in admincenter and validate cluster

User1: matlabpool(96) = success - currently actively running jobs

User2: matlabpool(10) = success

User2: matlabpool(20) = failure

    Error using
    parallel.internal.pool.InteractiveClient>iThrowIfBadParallelJobStatus
    (line 780)
    The interactive communicating job errored with the following
    message: Cannot rerun task because there are no rerun attempts
    left (task has no rerun attempts left).
    Original cancel message:
    The worker MATLAB exited or was stopped during task evaluation.
    MATLAB ended with exit status 9.

[Edric Ellis]

This is not expected - I suggest you contact support to help resolve this problem.