Issue finetuning SSD example

I am trying to follow the example for object detection here

but I am hitting the followiong issue which I have reported here

Traceback (most recent call last):
File “train.py”, line 148, in
tensorboard=args.tensorboard)
File “/home/aschu/development/ssd-sample/mxnet-ssd/train/train_net.py”, line 252, in train_net
_, args, auxs = mx.model.load_checkpoint(prefix, finetune)
File “/home/aschu/.virtualenvs/ssd/local/lib/python2.7/site-packages/mxnet/model.py”, line 420, in load_checkpoint
symbol = sym.load(’%s-symbol.json’ % prefix)
File “/home/aschu/.virtualenvs/ssd/local/lib/python2.7/site-packages/mxnet/symbol/symbol.py”, line 2518, in load
check_call(_LIB.MXSymbolCreateFromFile(c_str(fname), ctypes.byref(handle)))
File “/home/aschu/.virtualenvs/ssd/local/lib/python2.7/site-packages/mxnet/base.py”, line 146, in check_call
raise MXNetError(py_str(_LIB.MXGetLastError()))
mxnet.base.MXNetError: [22:41:43] src/io/local_filesys.cc:166: Check failed: allow_null LocalFileSystem: fail to open “/home/aschu/development/ssd-sample/mxnet-ssd/output/exp1/ssd-symbol.json”

I have downloaded the sample data set and created the .rec/.idx files using the included prepare_pascal.py script.
I get this error when calling train.py

In case anyone else has this issue, I just copied the pre-trained model files (*.json and *.params) to the “output/exp1/” directory, then renamed them to ssd-symbol.json and ssd-001.params and now it appears to be working.