Looks like you're missing a library file. The program apt-file can be used to find which package provides a certain file. (dpkg -S does this too, but does not work for packages which are not installed)
apt-file search libXss.so yields:
ia32-libs: /usr/lib32/libXss.so
ia32-libs: /usr/lib32/libXss.so.1
ia32-libs: /usr/lib32/libXss.so.1.0.0
libxss-dev: /usr/lib/libXss.so
libxss1: /usr/lib/libXss.so.1
libxss1: /usr/lib/libXss.so.1.0.0
libxss1-dbg: /usr/lib/debug/usr/lib/libXss.so.1.0.0
You need to install the libxss1 package for that library. If you're running the 32-bit version of Skype, ia32-libs needs to be installed instead of libxss1.