I have been trying use apt-get to install a few things but I keep on getting errors dpkg. Here is the log:

Nokia-N800-51-3:~# apt-get install kernel-diablo-modules-extra portmap
Reading package lists... Done
Building dependency tree... Done
portmap is already the newest version.
The following NEW packages will be installed:
kernel-diablo-modules-extra
0 upgraded, 1 newly installed, 0 to remove and 131 not upgraded.
2 not fully installed or removed.
Need to get 0B/159kB of archives.
After unpacking 455kB of additional disk space will be used.
WARNING: The following packages cannot be authenticated!
kernel-diablo-modules-extra
Install these packages without verification [y/N]? y
(Reading database ... 29488 files and directories currently installed.)
Unpacking kernel-diablo-modules-extra (from .../kernel-diablo-modules-extra_2.6.21-200842maemo1.2_all.deb) ...
dpkg: error processing /var/cache/apt/archives/kernel-diablo-modules-extra_2.6.21-200842maemo1.2_all.deb (--unpack):
trying to overwrite `/lib/modules/2.6.21-omap1/extra/lockd.ko', which is also in package rx-34-kernel-modules-extra
dpkg-deb: subprocess paste killed by signal (Broken pipe)
Errors were encountered while processing:
/var/cache/apt/archives/kernel-diablo-modules-extra_2.6.21-200842maemo1.2_all.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)
Nokia-N800-51-3:~#

Isn't it clear enough?

That really doesn't help me figure out how to fix it. Do I just remove the lock file? Shouldn't apt-get be taking care of these sort of issue with me having figure how to fix it manually?

That isn't a lock file, it's a kernel module file. The issue you've got is that the kernel-diablo-modules-extra package you're trying to install contains some of (or all of) the same files as the rx-34-kernel-modules-extra package you already have installed. This prevents them from being installed at the same time (without forcing things anyway). I'd advise checking whether you already have the necessary kernel modules installed as part of rx-34-kernel-modules-extra, or removing it before installing the kernel-diablo-modules-extra package.