Installing VC Games (wad files)

Ok I've installed the homebrew channel, I've installed some Virtual Console games and some Wiiware however one or two are giving me problems. For example I tried to install Excitebike and received the following error:

Installing ticket ERROR! (Ret = -1020)

It doesn't seem to attempt to install it just errors out straight away. Any ideas? I've successfully installed Nebulus and Summer Games simply by putting the relevant wad file into the wad folder and installing it via homebrew channel.

Is it likely to be the source (where I acquired the wad from) or something else?

I won't ask where's the best place to get wads from..

Its WiiBrew does not support or condone the installing of commercial WADs. In most cases its also illegal. Such being the case, discussion of it is prohibited in this forum.