I have a 30 gb hard drive with two linux partitions on it. Anyway, I'm already using one partition for Mandrake 10.0, and the other one is empty. Everytime I try to mount the empty partition (even as the root) it says "Permission Denied". Anyone know how to fix this?

Could you post your /etc/fstab file?

Most typical default installs create more then one partition. To see how the drive is partitioned.
(log in as root via su)

fdisk -l /dev/hda (that is a small L, Replace hda with the actual device of the drive)

Post the results. Which partition are you trying to mount?

Here's what's in my /etc/fstab:

/dev/hda1 / ext3 defaults 1 1
none /dev/pts devpts mode=0620 0 0
/dev/hdd /mnt/cdrom auto umask=0,user,iocharset=iso8859-1,codepage=850,noauto,ro,exec 0 0
none /mnt/floppy supermount dev=/dev/fd0,fs=ext2:vfat,--,umask=0,iocharset=iso8859-1,sync,codepage=850 0 0
/dev/hdb1 /mnt/windows vfat umask=0,iocharset=iso8859-1,codepage=850 0 0
none /proc proc defaults 0 0
none /mnt/hd supermount dev=/dev/ide/host0/bus0/target1/lun0/part1,fs=ext2:vfat,--,umask=0,iocharset=iso8859-1,kudzu,codepage=850 0 0

It's a EXT2 patition.

When I tried fdisk -l /dev/hda2/ in the terminal, it just started a new line.

Do not specify the partition ID.
fdisk -l /dev/hda

Here it is:
Device Boot Start End Blocks Id System
/dev/hda1 * 1 20310 10236208+ 83 Linux
/dev/hda2 20311 50822 15378048 5 Extended
/dev/hda5 20311 50822 15378016+ 83 Linux

hda2 is an extended partition and can not be mounted. In a nut shell it is a container for logical partitions. Any partition >=5 is a logical. In the beginning of drive history one could only create 4 partitions. Since only 4 partitions wasn't enough the extended / logical scheme was developed. The original partitions are now known as primary and have an ID of 1-4.

What you are trying to mount is /dev/hda5.

mount -t ext2 /dev/hda5 /mnt/<where_ever>

You will need to create a directory using the mkdir command prior to mounting the partition.