I havent really researched this much further (yet), but I wanted to let you
know, that on amd64 with sarge+bpo the following happens:
apt-get -t sarge-backports install apache2 php5-mysql php5 phpmyadmin
libapache2-mod-php5 php5-curl php5-imap php5-gd
The following packages have unmet dependencies:
php5: Depends: libapache2-mod-php5 (>= 5.2.0-8~bpo.2) but 5.1.6-1~bpo.1 is
to be installed or
libapache-mod-php5 (>= 5.2.0-8~bpo.2) but 5.1.6-1~bpo.1 is
to be installed or
php5-cgi (>= 5.2.0-8~bpo.2) but it is not going to be
installed
Depends: php5-common (>= 5.2.0-8~bpo.2) but 5.1.6-1~bpo.1 is to be
installed
E: Broken packages