problem importing raw heightmap

Hi there. This might be a problem on my side but maybe you can help? I try to import a RAW heightmap into L3DT but get an fseek error
CL3DTio_RAW_HF::LoadMapFile error:
- fseek failed for file 'C:\new1 big.raw'
CL3DTio_RAW_HF::LoadMapFile error:
- fseek failed for file 'C:\new1 big.raw'