Published image galleries and contact sites cannot be opened.
The following error appears: "Unable to load the webpage because the server sent no data."
There is also an error message in /var/log/apache2/error.log :
/usr/sbin/apache2: symbol lookup error: /usr/lib/php5/20060613/xsl.so: undefined symbol: INI_INT
The problem is caused by the Debian PHP package bug 658088 for PHP 5.2.6.dfsg.1-1+lenny14.