I have tried on several occasions to write to specific files for example; I downloaded a package gtkpod-0.99.12.tar.gz and tried to add it to usr/local/packages using KGet but was unable because it would not allow me to do so. How can I download packages and put them where they need to go so I can use GSlapt to unpackage and load them onto my computer? TC.
There are really a couple of questions there...
First, other than your home directory, you will find that you do not have permission to write files in many other places unless you give yourself root (superuser) access. For downloading, the easiest is to make a directory under your home directory and download files to that directory. They can then be moved later using root access, if necessary. Downloading using root access is not a good idea.
Second, I think you are making an assumption. The example you give looks more like a source file than an application, so there is little chance that Gslapt will be able to do anything with it at all.
For packages, use Gslapt (make sure you have all the repositories that you need enabled) and let it download and install applications. If you can't find an application that you want in the Vector repositories, at least some Slackware packages will work. For packages that do not seem to have a Vector or Slackware version, you will either need to compile and install them yourself, or request someone to build a package for you - there is a section on the forum for that purpose.
Hope that helps a bit...