You should make sure that the Wiimote is synchronized with your Wii. If it is, you should hold down 1+2 buttons on the remote until it connects. If that doesn't work, replace or recharge the batteries.
I have this problem in Gamma with WarioWare & Trauma Centre. The Wii refuses to accept another Wiimote while playing these two. It's not a problem with the batteries, sync etc because it will work perfectly straight after if I load a different game. At first I though it might have been down to a bad burn but after reburning the problem is still there.
i think this is a bug in backup loader. I get the same problem in many ea sports games like Madden and nba live. Game locks up at the wii remote startup screen thing, and wont connect to any of the remotes. All other games work perfectly.