Mariam,
Erbitux is a relatively new player compared to the older platinum componds. Both platinum compounds act by damaging DNA, if enough DNA is damaged the cells give up and die (those that grow quickly). They make the cells more susceptible to radiation damage (radiosensitizers). This is quite commonly used in H&N cancers.

For the Erbitux please follow this follwing link:
http://www.cancer.gov/clinicaltrials/results/head-neck-cetuximab0604

In short Erbitux helps compared to radiation alone. But you need to read the limitation (in that text), especially with respect to platinum/radiotherapy. (platinum/RT was NOT compared to Erbitux/RT). The effectiveness of Erbitux depends on the type of cancer. Many head and neck cancers overexpress epidermal growth factor receptor (the target of Erbitux).

They conclude ....At present, for patients who can tolerate it, chemoradiotherapy with cisplatin remains the standard of care."
There may be newer data available of which I am not aware!

On a different note: I was supposed to get Erbitux myself. In some people (2-3%) it causes serious complications and I landed in the ER (anaphylactic shock). Fortunately, this is quite rare. What still irks me is the audacity of my former MO who sent me a bill for his "treatment" despite the fact that he was alerted by me and my GP that I may be sensitive to Erbitux. We agreed on a test dose.... (It also did not help that his oxygene bottle was empty)
Subsequently, I had weekly cisplatin then carboplatin treatments (different MO) along with IMRT.

Best

Markus