Allocating/mapping single buffer failed with: clEnqueueWriteBuffer(-4). GPU can't allocate

Hi Dears, I had some errors:

[OPENCL]:Allocating/mapping single buffer failed with: clEnqueueWriteBuffer(-4). GPU can't allocate the DAG in a single chunk. Bailing.
[OPENCL]:clEnqueueWriteBuffer(-38)

what does that mean?

I have this configuration on ubuntu:
Listing OpenCL devices.
FORMAT: [deviceID] deviceName
[0] GeForce GT 740M
CL_DEVICE_TYPE: GPU
CL_DEVICE_GLOBAL_MEM_SIZE: 2101542912
CL_DEVICE_MAX_MEM_ALLOC_SIZE: 525385728
CL_DEVICE_MAX_WORK_GROUP_SIZE: 1024

and I start the process using this script:

#!/usr/bin/env bash
export GPU_FORCE_64BIT_PTR=0
export GPU_MAX_HEAP_SIZE=90
export GPU_USE_SYNC_OBJECTS=1
export GPU_MAX_ALLOC_PERCENT=90
export GPU_SINGLE_ALLOC_PERCENT=90
ethminer --farm-recheck 200 -G -F http://127.0.0.1:8080

How can I solve this error?