You might get assistance in the Citrus Forum.

http://forums.gardenweb.com/forums/citrus/

And tell those folks where you live, also is the plant indoors or out.

Beyond that, it's normal for more than half the tiny citrus fruits to drop.

Here is a link that might be useful: Citrus Forum

I am having the same problem but I came to know recently that if you are new to lime trees, you have to know how to find the "graft line" on the tree and cut all the branches below the line which are referred to as "suckers" as they take the nutrients from the tree and do not allow the fruit to mature. Also a citrus fertilizer is important.

I just use a Sunnyland or Hi-Yield, I believe it is 8-6-6. Use it April, June, and September. In Oct, potash to help overwinter and for the tree to accept the fert better in April. Use 1 lb for every inch of trunk diameter, 7 to 10 inches from the trunk, to the drip line.

Don't worry about my Missouri zone, I just moved here from FL. I had a three year old Satsuma that I pruned all the way back and ripped it from the ground, lol. It and my Key Lime are doing great in big ole pots, overwintering in the house.

The graft line will usually look like a slight bend in the tree trunk near the ground, almost like a defect (which I suppose it really is).

Best of Luck!

Cheri