If she is getting them in the home perhaps treating your floors will help.
I use this product which works well for me.
http://www.petco.com/Shop/Product.aspx?familyid=3057
If the are out in the yard then try an insect growth regulator in the yard area.
http://www.pestproducts.com/fleasoutside.htm
If she is picking them up on walks all you can do is make sure they don't live long and Frontline in combination with the floor spray should take care of that.
Make sure you are getting your Frontline from a reputable source. I've heard there is some 'black market' product out there that doesn't work as well but is being sold as the real thing.
Hope this helps you!
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