FOC requested 2 years of tax returns to determine child support. Can they take the 10-99, non-adjusted gross from the yr the taxes were not done yet?

Your question is a bit confusing and you failed to indicate how long ago the matter was heard and ultimately decided. Therefore, I will assume in this answer that the FOC requested the last 2 years personal income tax returns from you and that you were unable to provide the one for last year (2010) as it has yet to be completed and filed.  That being the case the FOC will look at what you have provided and if they cannot determine the appropriate amount of adjusted gross income for the incomplete year then the only thing they have to go on is the last completed return and any year to date income info you can provide.  If you did not agree with the recommendation when it was made you had 21 days to file objections and request a de novo hearing before the judge.  If you failed to object timely then you have probably lost your opportunity to argue the point. If your income is different now, you can file a motion to modify the support.