Im a newbie to linux and decided to try it Slackware Linux. I've probley tried to install this thing about ten times but kept failing.

Anyway, booting off the diskittes and creating a parpartion of a the hard drive wasn't really hard as much. Its at the end of the setup that im having trouble with.

setting a target to the parpartion, and selecting the source media wasn't trouble as well. My current problem is, I tried to install the full installation of slackware that included in the package. It ranked up around 2 gigs. After it was complete, I did the reboot. After booting, No operating system was detected and couldn't install.

I went threw the entire process again, and chose newbie instead. The following error I recived was

Mount Error

Your source device cannot be accessed properly

Please be sure that it is mounted on /var/log/mount/slackware, and that the slackware disks are found in the subdirectores of /var/log/mount/slackware like specified.

I was wondering if I need some third party tool to mount the files and install?

EDIT: I found out that problem, but the packages couldn't have installed quickly. The screen flickered, and it required me to reboot.

I think that you have the system installed. You don't have a bootloader, so you can't boot, but it can be fixed. Do you use boot cd or boot disks? You need to boot Linux (can be the point you now get the error message). Then you need to mount all the partitions. First create the mount point:
mkdir /mnt
Then mount all the partitions: / as /mnt, /boot as /mnt/boot and so on. If you have one Linux partition, use
mount -t ext2 /dev/hda1 /mnt
When they're mounted, edit /mnt/etc/lilo.conf
Check if you have:
boot=/dev/hda
and something like
image=/boot/vmlinuz
label=linux
root=/dev/hda1
read-only
Then save the file and run
chroot /mnt
lilo
LILO should install. You can reboot and test it.