That is normal, here's an explanation as to how channels installed to the sd card work
When you install a channel, everything, including its ticket, is installed to your Wii's real nand. When you move channels to the SD card menu, it moves all the game data to the SD card, but the ticket stays on the real nand. And if you try to launch a channel from the SD card menu and its ticket is not installed to the real nand, it will not work. This is to ensure that people cannot share channels they have not legitimately purchased.
There are 2 ways to get around this
1) the simplest is to make a nand dump of your Wii that is able to launch the channels from the SD card menu, then extract the nand dump to your USB HDD using showmiiwads (details on how to do so can be found here:
http://gbatemp.net/t218725-sneek-di-quick-guide). So this will make an exact copy of your nand, and it should have the tickets on it required to launch the games you've moved to the sd card menu.
2) You can reinstall all the channels again to your emulated nand, then move them to the SD card menu (or if they're already on the SD card menu, u can just delete the channel via the Wii System Menu, this will delete the game but it should keep the ticket installed, allowing you to play the title that you already have on the sd card)
FYI, if u have any channel in wad form, u can install it to the emulated nand using showmiiwads.