There is a forum for surname questions and discussion - someone will be able to help you there.
http://surnames.behindthename.com/bb/sur
From my knowlege of French I can tell you that
peau means "skin" and
chate looks like a variation of
chat (cat).
Peaudechate would then mean "cat skin." I'm no expert, though, so someone on the surnames board can verify that for you.
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PNL:
http://www.behindthename.com/pnl/74055