Hello.
That means your Wii does not have the Gamecube Ports.
Unfortunately your Wii Modell can not read the Gamecube Discs anymore.
You can try to find a "Way" to get your Games to the Wii´s SD Card or an FAT32 formatted USB HDD to play it with Nintendont/USBLoader GX.
That means,your Gamecube Games has to be "ripped" or "converted" to the ISO Format.
Normally this can be done with the USBLoader GX or the CLEANRIP Tool on an Softmodded Wii.
Since your Wii can not read the Gamecube Discs it is maybe a little difficult,you need
- a specific Brand/Type if PC DVD Drive that can read the Gamecube DVDs.
or
- a Softmodded Gamecube or Wii
or
- an "other" way to "find" already "converted" Games.
I hope this helps you a little.
Good luck.
Thank you.