Run the following commands as a regular, non-root user. You'll need the root password to install them.

1. Install nxproxy from git

$ git clone git://code.x2go.org/nxproxy
$ cd nxproxy
$ autoconf 
$ ./configure --prefix=/usr
$ make
$ su -c "make install"

2. Install x2goclient from git

$ git clone git://code.x2go.org/x2goclient
$ cd x2goclient
$ qmake
$ make
$ su -c "install -m 755 --owner root --group root -c -D x2goclient /usr/bin/x2goclient"