Proper Archive Structure

Top Level
Make sure your archive is a *directory* instead of individual files. Make sure the directory contains the required files.

application/

Files
This is a list of minimum required files for submission:

application/application.SlackBuild
application/application.info
application/slack-desc
application/README

Creating the archive
You can create a suitable archive using one of the following commands:

tar cvf application.tar application/
tar zcvf application.tar.gz application/
tar jcvf application.tar.bz2 application/