You are a May 2011 applicant?

OMG you are LUCKY

Yes I have applied in May 2011. Thanks
My status is changed to "In Process" and New line is added "Your application was reviewed and we started processing on April 18 2012" on 23 of April.
And I also Got a letter requesting additional documents :-
This refers to your application for permanent residence in Canada.
In order to continue processing your application, the following is required:
1. Work and Residence History From Jan-2011 to Present.
2. Updated Job Offer letter from Canadian Employer
3. 2003, 2004, 2005 and 2006 India Tax Return
They have given 60 days to submit requested documents
what does it means , if i submit requested docs then they will issue medical request form? or is it negative sign?
Regarding the updated job offer, I already ask to my employer and he will provide the updated job offer letter.
My main consern is :-I didnt file tax for the given period, my income was lesser than minimum income needed to eligible for tax--
and I have 6 years of experience, but i have only 2.5 years of check salary, rest i got in cash.
What should i do for the tax return? I am so worried about it, Please Advise
Thanks,
Manish