Hi,
I arrived from Italy back in Sept. 2001 and was a visiting lecture at a US College. I taught there from Sept. 2001 through May 2004. I was never told about the use of a tax treaty when I filled my returns. I have a friend now doing my taxes as I have returned to get my PHD and he brought this oversite to my attention.
I know the statue of limitation of 3 years to file for amendment has expired for the tax year of 2001 and 2002. Am I still able to apply for an abatement for tax year 2003 for part of the year? Also is there any way I can try to get an abatement for 2001 and 2002 since the person who did my taxes didn't disclose to me the benefits of the tax treaty?
Thank you for any help you can give me

You can request an abatement for all three years, but as of today, the deadline to revise 2003 has also passed.

All they can do is say NO to your request.