Fedora X86/64bit :: Installing RPM - Yum Output Via Terminal Error

I'm new to Fedora and the Red Hat way of doing things, having been a Ubuntu/Mint user for the last 5-6 years. I've been using Fedora for my daily computer now for the last 3-4 months - a change that has definitely been for the better! However, earlier this morning I went to install a .rpm, and yum output via terminal the following error:

Code:
[leeky@darkstar ~]$ sudo yum install opera
[sudo] password for leeky:
Loaded plugins: fastestmirror, langpacks, presto, refresh-packagekit
Adding en_US to language list
Loading mirror speeds from cached hostfile
* fedora: mirror.netrino.co.uk
* rpmfusion-free: mirror01.th.ifl.net
* rpmfusion-free-updates: mirror01.th.ifl.net
* rpmfusion-nonfree: mirror01.th.ifl.net
* rpmfusion-nonfree-updates: mirror01.th.ifl.net
* updates: mirror.netrino.co.uk
Error: database disk image is malformed
[leeky@darkstar ~]$

This is the first time I have received this error. I've now tried the following methods of resolving this problem with no luck:

1. Code:
yum clean all
2. Code:
yum clean metadata
yum clean dbcache
yum makecache
3. Physically removing the /var/libs/yum folder, and creating a new "yum" folder, and then step two above to rebuild it. Either way the problem then still returns in terminal.