Qiagen DNAeasy blood&tissue DNA isolation kit - (Jul/29/2009 )

Is there anyone use Qiagen DNAeasy blood&tissue DNA isolation kit? I was useing this kit to isolate DNA from the tail of mice for genotyping. I had a lot of problem with the genotyping PCR these days. I changed the PCR reagents, but still don't work. Then I measured the DNA concentration and found that the concentration is as low as 20ng per microlitle.
I am asking if anyone here had the same bad experience and any of your suggestion will be appreciated.
thanks

How old is the kit? Are any of the buffers out of date / stored at the wrong temperature / precipitated?
Also I find the recommended final elution step can be too high, I only use 30ul as a standard