CellProfiler is optimized for fluorescent images. Unless your DIC images have good contrast, cell segmentation is unlikely to work well, much less sub-compartment segmentation (such as identifying nuclei from the cell). In this case, the DIC image seems to be saturated and the outlines of the nuclei, though somewhat visible by eye, will probably not be distinguishable by automated means.
Still, take a look at forum
page under item 5. You may find some helpful hints there.