Error in Testing with MXNet in Detection Task

I am running my Project (MXNet framework). I delete by accident my output file of the model, but then(i have made a new one) i get this error:

 raise MXNetError(py_str(_LIB.MXGetLastError()))
mxnet.base.MXNetError: [22:55:01] src/io/local_filesys.cc:166: Check failed: allow_null  LocalFileSystem: fail to open "./output/dff_rfcn/imagenet_vid/resnet_v1_101_flownet_imagenet_vid_rfcn_end2end_ohem/VID_val_videos/../DET_train/dff_rfcn_vid-0002.params"

I have sometimes in past the same delete, but my program was still testing good.What's going on?