Salix OS

I am relatively new to Linux (I have been using it for about 8 months) and recently have been experiment with Salix in my Virtual Box. I am very impressed so far. However, there are a couple of packages that I could not find in the repository so I am trying to add them with SlackBuild. The packages are skrooge and pdfedit. I tried to work with pdfedit first but am getting an error message when I run the SlackBuild script. The error message says
Can anyone help me figure out what could be causing this error? Thanks.

You need to install doxygen package first, available in Salix repo through gslapt or slapt-get.

Sometimes, you need some package to compile a software, even if it is not needed when installing/using that software. doxygen is typically that kind of "compile depedancies".