"box 2" on my w2 is empty... am i doing somethig wrong??

If it empty then there was no Federal tax withheld.  
If you think that is not correct, ask your employer.

thanks

If Box 2 on your Form W-2 is blank, that means your employer is reporting that no federal income tax was withheld from your paychecks.

It may be correct but I would first verify that by reviewing your paystubs and speaking with your employer.