Hi.  Base_convert interprets letters w,x,y, and z to be zero but should handle letters up to z: "Digits in numbers with a base higher than 10 will be represented with the letters a-z, with a meaning 10, b meaning 11 and z meaning 35." -- http://www.php.net/manual/en/function.base-convert.php

Shows problem:
$base32 = 'x';           // a-v ok, w-z=0
$base10 = base_convert($base32, 32, 10);
echo "base10: $base10\n";

My configure line:
./configure --with-cybercash=/usr/local/bin/mck-3.3.0-i586-pc-linux-gnulibc2.1 --with-pgsql=/var/lib/pgsql --with-apxs

thanks,
George