'port install' can't find variable declared in variant

[Bjarne D Mathiesen]

I've got this Portfile :

# -*- coding: utf-8; mode: tcl; tab-width: 4; indent-tabs-mode: nil;
c-basic-offset: 4 -*- vim:fenc=utf-8:ft=tcl:et:sw=4:ts=4:sts=4
# $Id: Portfile 89615 2012-02-04 05:28:00Z ryandesign at macports.org $

PortSystem                      1.0
PortGroup                       php5extension 1.1
PortGroup                       archcheck 1.0

php5extension.setup             {mysql mysqli pdo_mysql} 5.3.11 bundled
categories-append               databases
platforms                       darwin
maintainers                     ryandesign
license                         PHP-3.01

description                     a PHP interface to MySQL databases,
including \
                                the mysql, mysqli and pdo_mysql extensions

long_description                ${description}

checksums                       rmd160
cdad550e94cb911fa68b99acba2a5925d0848cf3 \
                                sha256
b4174c97ca8d8bcf4b52b8b9ef2c2f35e1b611a5a660e02d7cd3edf263a6bd5d

depends_lib-append              port:zlib

use_parallel_build              yes

configure.args-append           --with-mysql=mysqlnd \
                                --with-mysqli=mysqlnd \
                                --with-pdo-mysql=mysqlnd \
                                --with-zlib-dir=${prefix}

configure.cppflags-append       -I${worksrcpath}

variant mysql51 conflicts mysql55 mariadb percona description { mysql51 } {
    set  mysqlver  "mysql51"
}

variant mysql55 conflicts mysql51 mariadb percona description { mysql55 } {
    set  mysqlver  "mysql55"
}

variant mariadb conflicts mysql51 mysql55 percona description { mariadb } {
    set  mysqlver  "mariadb"
}

variant percona conflicts mysql51 mysql55 mariadb description { percona } {
    set  mysqlver  "percona"
}

post-destroot {
    reinplace "s|@PREFIX@|${prefix}|"   ${php5extension.iniFile}
    reinplace "s|@MYSQL@|${mysqlver}|"  ${php5extension.iniFile}
}

When I use it, I get :

bash-4.2# port install php5-mysql +mysql55
--->  Computing dependencies for php5-mysql
--->  Fetching archive for php5-mysql
--->  Fetching php5-mysql
--->  Attempting to fetch php-5.3.11.tar.bz2 from
http://lil.fr.distfiles.macports.org/php5
--->  Attempting to fetch php-5.3.11.tar.bz2 from
http://fi.php.net/distributions/
--->  Verifying checksum(s) for php5-mysql
--->  Extracting php5-mysql
--->  Configuring php5-mysql
--->  Building php5-mysql
--->  Staging php5-mysql into destroot
Error: Target org.macports.destroot returned: can't read "mysqlver": no
such variable
Log for php5-mysql is at:
/macports/var/macports/logs/_Volumes_Bjarne_WebServer_MacPorts_newPorts_php_php5-mysql/php5-mysql/main.log
Error: Status 1 encountered during processing.
To report a bug, see <http://guide.macports.org/#project.tickets>

Now, can anyone tell me what I'm doing wrong ???

thanks,
-- 
Bjarne D Mathiesen
København N ; Danmark ; Europa
----------------------------------------------------------------------
denne besked er skrevet i et totalt M$-frit miljø
MacOS X 10.7.3 Lion ; 2.8GHz Intel Core i7 ; 16GB 1067MHz DDR3