matlab使用caffe.solver()載入solver總是失敗。

我使用MATLAB的載入solver的功能，想載入示例中的lenet_solver.prototxt。（這個我使用命令行是可以用的）
>> solver = caffe.Solver('./examples/mnist/lenet_solver.prototxt')
之後出現以下：
WARNING: Logging before InitGoogleLogging() is written to STDERR
I0312 17:59:42.972985 20694 solver.cpp:48] Initializing solver from parameters:
test_iter: 100
test_interval: 500
base_lr: 0.01
display: 100
max_iter: 10000
lr_policy: "inv"
gamma: 0.0001
power: 0.75
momentum: 0.9
weight_decay: 0.0005
snapshot: 5000
snapshot_prefix: "examples/mnist/lenet"
solver_mode: GPU
net: "examples/mnist/lenet_train_test.prototxt"
I0312 17:59:42.996278 20694 solver.cpp:91] Creating training net from net file: examples/mnist/lenet_train_test.prototxt
I0312 17:59:43.020938 20694 net.cpp:322] The NetState phase (0) differed from the phase (1) specified by a rule in layer mnist
I0312 17:59:43.021008 20694 net.cpp:322] The NetState phase (0) differed from the phase (1) specified by a rule in layer accuracy
I0312 17:59:43.021159 20694 net.cpp:58] Initializing net from parameters:
name: "LeNet"
........中間的網絡描述省略
layer {
  name: "loss"
  type: "SoftmaxWithLoss"
  bottom: "ip2"
  bottom: "label"
  top: "loss"
}
I0312 17:59:43.021317 20694 layer_factory.hpp:77] Creating layer mnist
I0312 17:59:43.046411 20694 net.cpp:100] Creating Layer mnist
I0312 17:59:43.046473 20694 net.cpp:408] mnist -> data
I0312 17:59:43.081159 20694 net.cpp:408] mnist -> label
I0312 17:59:43.124948 20862 db_lmdb.cpp:35] Opened lmdb examples/mnist/mnist_train_lmdb
Unexpected unknown exception from MEX file..

Error in caffe.get_solver (line 7)
pSolver = caffe_('get_solver', solver_file);

Error in caffe.Solver (line 21)
        self = caffe.get_solver(varargin{:});

每次都會出這樣的問題。哪位前輩指導一下？謝謝大家！