This study uses the drug PPX (also called Xyotax and CT-2103) in women with advanced colorectal cancer. PPX is an experimental drug that has not been approved by the Food and Drug Administration (FDA). PPX has been shown in the laboratory and in studies in humans to cause some cancer cells to die and some tumors to shrink. Women in some studies with PPX have been shown to live longer than the men that receive the drug. Some studies in humans suggest that estrogen (a hormone found in women) may protect women from getting colorectal cancer and allow women that do get colorectal cancer to live longer than men that do.