setup imail with gmail??not working. why?

Hello all
please can anybody tell me why my gmail account is not working on my imac imail?please read the my story:-
i work as an sales marketing person for my company and most of the time im on the movemeeting clinets so i wanted that all my companies email (my company has domain-tfgroup.com) should be forward to my gmail account and also i use my personal gmail account configured in my imac-imail but the problem is i cant not able to get any email.why?
All i wanted is that:
i should be able to differently handle the company and my persoanl email in apple imail software?

TGGROUP.com >forward> gmail (imail)
-----------------------------------
MY Gmail account >forward> gmail setup in (imail)

Firstly check you gmail on the web to be sure you're receiving the forwarded emails.

Then configure your gmail and Apple Mail client using these instructions:
Apple Mail 4.0 - Gmail Help