Temsirolimus (CCI-770, Torisel) Combined With Cetuximab in Cetuximab-Refractory Colorectal Cancer

* Because this is a study to determine the highest dose of cetuximab that can be safely given with temsirolimus, groups of 3 participants will be treated at gradually increasing doses of cetuximab. Each group of 3 participants must complete 4 weeks (1 cycle) of treatment before the following group of 3 participants can start treatment at the higher dose. * Cetuximab is administered intravenously 7 days before the treatment cycle begins. Participants will receive a cetuximab infusion every week of the treatment cycle (days 1, 8, 15, 22) along with temsirolimus. Temsirolimus is also given intravenously. * As a precaution, participants will be pre-medicated with Benadryl/diphenhydramine to help prevent an allergic reaction. * During the study participants will have weekly clinical visits. Each clinic visit will last approximately 2-3 hours. During the clinic visit, the following tests and procedures will be performed: Physical exam; vital signs; and blood tests. A CT scan will be performed after every 2 cycles (8 weeks). * Pharmacokinetic (PK) blood samples will be taken at various points during the study. For each PK sample, we will take about 1 teaspoon of blood. There will be a total of 22 tubes of blood taken for the PK study.