In case Priiloader hasn't been working and haven't found the solutions, how about a shot at BootMii?
For right now, I'm going to guess you are already hacked and have HBC installed(I'll go over unmodded Wii's near the end)
1)Go to http://bootmii.org/download/ and Download HackMii Installer v1.2.
2)Place the HackMii folder in your apps folder you use for HBC
Ex: SD Root\apps\hackmii folder here...
3)Go to HBC and there should be an app without a logo, just blank, but when you go to open it, it should be titled HackMii.
4)As soon as you open it, an image should pop up stating "THIS SOFTWARE MUST NOT BE SOLD" blah blah blah, some more scammed mumbo jumbo. It will stay on this screen for a good 20 seconds, just be patient. After some time, on the bottom, it'll state: "Press 1 to continue"
5)You will be taken to some text saying " The test results are in:" and "The Homebrew Channel: Can be installed", "BootMii: Can be installed". Here you just wanna press continue.
6)You will be at the Main Menu(you can tell by the yellow letters at the top), go to "BootMii..."
7)There are a lot of options here so listen(or read) carefully:
Letters in Cyan are taken directly from the README-BootMii.txt.
* BootMii/boot2: This mode will install BootMii into 2 blank blocks in the
boot2 area of your Wii. It will take over the function of
the normal boot2. If no SD card is detected or armboot.bin
is not found on the SD card, the drive slot LED will flash
briefly and the normal system menu will boot.
Pros: Independant of system menu and the rest of NAND flash. Can
boot even if the rest of the system is completely corrupted.
Allows for safe backup / restore of NAND flash from SD card.
Allows direct boot of The Homebrew Channel, or other
programs.
Cons: Relies on a vulnerability in boot1 that was fixed mid-2008;
if your Wii is newer than this, the HackMii Installer will
not allow you to install this form of BootMii. Installation
is complicated and slightly risky; we have tested it and
believe it to be safe, but a power failure at the wrong time
during installation could leave your system unusable.
* BootMii/IOS: This mode will install BootMii into your NAND filesystem as an
IOS (IOS254). It behaves identically to BootMii/boot2, but
you must launch it from a special program (The Homebrew
Channel, or your own code.)
Pros: Universal compatibility with all Wiis. Allows booting
arbitrary code on ARM / PPC. Supports speedy backup of NAND
to SD. Very safe to install.
Cons: Easily deletable or overwritten by a system update. NAND
restore is technically possible, but not safe because you
cannot boot to BootMii/IOS in case the contents of your NAND
flash are corrupted.
In Short:
-BootMii/boot2: uses some files to skip from your SD card to skip into the special loader from when you start your wii where you can use your gamecube controller to navigate into the HBC(where you can also use your GameCube controller in case you didn't know).
-BootMii/iso: you need to be in your HBC channel to activate... you need to go through the original system menu, so duhhh... not what we are trying to get done, it's counterintuitive.
8)You are going to choose "Install BootMii as boot2"
9)Some menacing runtime warnings will show up about violating your SD card, assuming it's in your Wii, click on "Yes, continue"
10)It'll write some files onto your SD card and ask you if you want to install BootMii/boot2 now, click on "Yes, continue" once more.
*The files installed are in a folder on the root of your SD card under:
SD Root\bootmii
*The bootmii folder is transferable, so you can put it in other SD's for your mods, so they as well can bypass system menu.
11)Some CMD prompts will show on screen writing and attacking those filthy NAND blocks 3 & 4, once it's done 'SUCCESS' should pop up, and click continue.
12)Hit "Return to the main menu"
13)Hit "Exit"
14)After reaching the HBC, turn off your Wii and turn it back on
15)The BootMii menu will pop up, going from left to right there are four options:
1 Most Left-Boot original Wii system menu.
2 Mid Left-Boot up to the HBC.
3 Mid Right-Load .dol from SD.
4 Most Right-BootMii settings.
Unmodded Wii's:
When following whatever guide you are reading to mod your Wii, when you are prompted to install HBC, install BootMii as well, so you have it from the Get-go.
You can load HackMii using Smashstacks as well, but sadly I never used Smashstacks so I have no experience there.
As some added bonuses, if the bootmii folder necessary to load the menu isn't found or does not work in any way, the disc drive's LED will flash once and the original system menu will load. Also, this extra menu doesn't replace the old one so it gives you a recovery option, technically making your wii unbrickable.
Letters in Orange are taken directly from http://wiibrew.org/wiki/Bootmii#Benefits to cite the second bonus above.
BootMii allows anything from Recovery modes (creating a practically unbrickable Wii), to lazy access of the Homebrew Channel. For example, if you have corrupted the System Menu, you can use DOP-Mii to reinstall the System Menu. Unfortunately, all homebrew currently require an IOS, because libogc requires one. However, there is Mini (a homebrew IOS-like software), which can be modified specifically for the program, ie, for better communication to the Linux kernel.