If they're in .rar format, it means they're a specific run first that goes with that theme. I checked all the links and they work fine.
Here's a nice tutorial by my friend frylok, who also have a lot of themes
I know there are a few tutorials out there already that explain how to install custom themes, but none of them seem to have everything covered. So heres my atempt to write my first tutorial and try to cover pretty much everything there is to know about installing themes. Heres a pack I put together that has everything you'll need.
Theme installer pack(we can't put them here)
4.1U default app(not allowed here)
4.1E default app (not allowed here)
The theme installer pack has the system apps for 3.2U/E and 4.0U/E, softmii tweak toy, mymenuify, and mymenu.(if you don't know what those are keep reading).
Theres a seperate link for the 4.1U and 4.1E system apps right below that.
If you use the 3.2E system app +rep OwneddMuch, he found it when I couldn't.
If you use the 4.1E system app +rep wadrockzz, he got it for me.
The basics:
A bad theme file CAN brick your Wii. ALWAYS have some kind of brick protection before installing any themes.
Themes only work on 3.2U/E or 4.0U/E or 4.1U/E firmware(I'm told a 3.2 theme "should" work on a 3.3 or 3.4 wii, but its unconfirmed if anybody tries it let me know what happens)
Right now there are 2 types of themes, the normal ones(they are 4 frame) and ones with 36frames. A 36 frame theme just means there are 36 diffenet images used in the empty channel animation which means the animation can be longer or slower.
Most of the time when you download a theme it will come as a .mym file, they can come as .csm or .app but .mym is the safest and most prefered way to share themes. I'll cover what to do with each file type further down.
The tools:
You will need mymenu. My menu is a program that will run on your pc and change a .csm into a .mym or .app.
You will need a copy of your original system menu file. The list for those:
00000042 3.2U
00000045 3.2E
00000072 4.0U
00000075 4.0E
0000007b 4.1U
0000007e 4.1E
There are 2 diffent programs that will install your theme onto your Wii:mymenuify, and softmii tweak.(I prefer mymenuify but I keep them both on my sd card) If one of these apps gives you an error while trying to install your theme the use the other, I have noticed some themes just will not work with softmii tweak and some will not work with mymenuify. Pick wich ever you like(or both) and move it into the 'apps" folder on your sd card. If you are using softmii tweak then you put the empty "softmii" folder into the root of your sd card.
Using mymenu:
Once you have downloaded and installed mymenu, open it up it will show you 2 white bars. The top bar says "source" the bottom says "MyMfile". You will click "browse next to the top bar and locate your original system menu file. Look at the list above to make sure you've got the right one.(for me, I would locate "00000072.app") then hit "browse" by the bottom box and locate the .mym file you want to use(if I wanted to install my joker theme, I would locate "Joker.mym") then hit "create mymenu" at the bottom and wait. A few seconds later a window will pop up and ask where you want to save your file and what you want to name it.
If you downloaded a .csm or .app file:
If you downloaded a file that is already a .csm or .app then you can just name it according to the method you to use to install it(see below.)
-Everything to this point is the same if you are using softmii tweak or mymenuify. I'll cover the name part in the next 2 sections-
Using mymenuify:
If you plan to use mymenuify to install your theme once you get the part where you have to name your theme you can name if whatever you like and add a .csm to the end of it.(using the joker example from earlier I would name my csm "joker.csm" I then move the .csm file to the root of my sd card, put it in the Wii, open mymenuify(either through homebrew or if you have a channel) locate the .csm you want to install. click ok and wait. When its done it asks if you want to exit or continue, hit exit and enjoy your new theme.
-If you downloaded a file that is already a .csm or .app just name it "whatever.csm"(Example: you download a file named mario.csm, just stick in on your sd card and load as normal. If you download a file named "00000072.appmario" rename it to "mario.csm" and install as normal)
Using softmii tweak:
If you plan to use softmii tweak to install your theme once you get to the part where you name your .csm you have to name it the same as your system menu file.(for example I would name mine "00000072.app')But you can add anything you want after the ".app" part(example:"00000072.appjoker")This way you will always know wich of your themes is wich. Then you move the .app file (example:"00000072.appjoker")into the softmii folder in the root of your sd card. Then you put your sd card into the wii open softmii(through homebrew or through a channel if you have one)locate the .csm you want to install follow the directs on screen. and enjoy your theme when done.
-If you downloaded a file that is already a .csm or .app just name it "your originalsystemmenufile.appwhatever"(Example: you download a file named "00000072.appmario, just stick it in the softmii folder on your sd card and load as normal. If you download a file named "mario.csm" rename it to 00000072.appmario" and install as normal. I used 00000072.app but you'll use wich ever applys to you. Look at the list above)
-That covers the basic themes. Look below for 36frame guide-
If the theme you've downloaded is a 36frame theme(most people will post weather its a 36 frame or not) You should have at least 2 files(some have 3)there should be a "runfirst.mym" file and a "run second.mym" file. You will use mymenu just like above but you will locate the "runfirst" file in the second box. This will create a .csm file just like before, you will then open mymenu again and this time in the top box open the .csm you just made and in the bottom box open the "run second file" create a .csm just like before, name it according to the method your gonna use and install just like above.
If the theme gives you a .csm and a .mym(thats the way I pack my themes, Im not sure if anyone else does it that way) then use mymenu and locate the .csm with the top box and locate the .mym with the bottom box. and finish up like above.
Example: If I downloaded a simpsons theme that is a 36frame theme, I would unrar it with winrar(or what ever program you use to unrar or unzip things) it gives me 2 files. The first is "runfirst.mym" and the other is "runsecond.mym" I use this file with my original system menu file and make a new .csm that I would name S1.csm(you can name it what ever you want)then I open mymenu again and use the "source" box to locate S1.csm and use the "MyM file" box to locate "runsecond.mym" and create a new .csm that I would name "simpsons.csm" or "00000072.appsimpsons" depending what I was gonna use to install it.
Example 2: If I download one of my awesome themes that is a 36frame theme like my Batman theme, I would unpack it and it gives me 2 files. "runfirst.csm" and "batman.mym" I use mymenu and locate "runfirst.csm" with the "source box" and open "batman.mym" with the "MyM file" box. Create a new .csm that I would name "batman.csm" or "00000072.appbatman" depending what I was gonna use to install it.
Pm me for a link to the full tutorial