As for "all libraries are specified"... in the ISPConfig "Install Instructions", which I call a "howto", there is a comment: "Important: Be sure to have installed gcc, flex....You also need to install the MySQL header files which normally come in a package called mysql-devel, mysql-dev, libmysql-devel or something similar." "Something similar"?? That tells me nothing. The 3 mentioned above did not exist when I searched for them (maybe I did miss something there...). It was those libraries that I was missing, and this comment was so generic, I had to search google to find the compile error and a quoted text of what to install with a sample apt-get. It would be nice if you included a specific library install command at this point, I was left guessing for an hour of so to find a solution...
Ok, this means you did not follow one of the howtos at all. Please go to the ISPConfig.org documentation page, scroll down the page, select the howto for your linux distribution and version and follow exactly the steps described there.