on vWii there's not a lot of choices.
having slots doesn't mean a lot. in a slot you can install what you want, so telling you have 249 doesn't provide information of WHAT you really installed in the slot 249.
What's important is the actual content inside the slot, not if your slot is used or free.
What you need :
d2x cIOS rev10 or rev10-alt
base 56 : most games are working with a base56
base 57 : few games not working with base 56 require base 57
base 58 : few games require base 58 (mainly USB/Music games)
You can install any other base (38, etc.) suggested by the d2x installer.
So, I suppose you followed tutorials and installed what has been told to you, so you probably have these 3 bases (56/57/58).
But if you installed v10-alt, then know that it's less compatible with EmuNAND than v10 normal.
v10-alt adds support for dual USB Port in detriment to EmuNAND compatibility.
don't follow guides telling you to install latest versions of everything, knowing what's the difference and choose what you really need.
If it still doesn't work with v10 (normal, beta52), then I don't know why it doesn't work for you.
Also, you don't need to install all the three slots!
you can install only one cIOS with base 56, that's all. If you don't play games which require an IOS 57 or 58, don't install cIOS base57 or base58. only install the one you need. if you have v10-alt in 249/250/251, then you can try to install v10 in slot 249 only, no need to replace the other two slots with v10. Games and homebrew only use one IOS at a time. Having multiple versions has no real purpose if you don't need it.