@page validation

Hello,

I copied this from the sample style sheet given in the 
documentation at w3.org:

42: @media print {
43: @page {margin:10%; }
44: th {display:none; } 
45: } 

and I get

Zeile: 43   Einlese-Fehler - @page {margin:10%; } 
Zeile: 45   Parse error - Unrecognized : } 

What is wrong?

Jochem Heicke
JHL Informations-Systeme GmbH