What did you do with the brine shrimp once you got them home?
Here's what I do with live brine: Setup a small tank (5 gallon). Fillit half way with CLEAN salted water (sp should be around 1.017 or so) with an airstone running. Add the brine. Keep tank where it gets no direct sun, and is cool (~65). Mark the water level on the side of the tank--add freshwater as needed to keep the water level there. Feed every three days with yeast culture (activated yeast in warm water and sugar--only a few drops).
I also checked with the LFS to know when the got their brine shipments, and bought them ASAP--the longer they sit at the store, the less likely they are to live long, IME. If the brine aren't active, if there's a strong odor, don't buy more than one feeding's worth.