If anyone wants to get a volume icon in the Fluxbox panel here is what I did (if this is wrong somebody please let me know because I haven't worked with Slackware a lot):
1. Download the Volumeicon source file from SlackBuilds.org. Here is the link to the file >
http://softwarebakery.com/maato/files/volumeicon/volumeicon-0.4.3.tar.gz2. Open your Download folder, right-click and select "open terminal here".
3. Type this in the terminal without the quotes, "./configure --prefix=/usr"
4. Type this in the terminal without the quotes, "make"
5. Type this in the terminal without the quotes, "su root" and then enter you root password.
6. Type this in the terminal without the quotes, "make install"
7. Go to your .fluxbox startup file and add this to it:
## Start volumeicon
volumeicon &
8. That's it!