that direct download limitation doesn't apply to what your doing.
What they mean is that you can't host them on your site as individual files or a pack, like as a mirror, weather you claim them or not. The restriction free distribution clause covers unencrypted files packaged with the game, because those are part of the artistic medium, and oddly, you often aren't even aloud to encrypt them as that would restrict free use, that part is weird but I think as long as you don't claim them as yours and ask people to download from the original site your off the hook for what ever nonsense they choose to do. Allot of it is your intent rather than active protection... That's part of why it's freeing.
Anything under creative commons is almost certainly good to go do to that, for instance.
Since your mixing them into a game, and the game isn't specifically based on sound effects, like a sound matcher or a sleep sound app, than your also free of that silly restriction.
It's worth emailing them if your curious, they often say to do that if your not sure anyway.
I've looked pretty deep into the licensing terms and looked up the finer print on it's own and I'm still confused with some of the more complex licenses, but I have a good idea of what they mean now.
And attribution isn't really hard if you just keep track of what your using when you pick it in a text document, or keep a sub folder for each sound mix your creating with all the original sounds in it. Keeping the original names also makes things easier, so you don't have to remember what you changed it too.
Either way, some of them allow you to just say music by (name of composer and website link) for instance, and with the others you can just say something like (sound effects by the following artists, artist name, website link, list of sounds titles, separator, next artist)
Sometimes you do have to put it in the credits of the game rather than an included document, and the credits have to be the type where you can't avoid them either, so it needs to be like on the title screen, but you don't have to list each sound file, and if they don't specify the title screen, than you could just have them show up only when you beat or exit the game for instance.
Even then I've never seen a website that doesn't let you email them to ask for an exception, and since your non commercial I doubt they would have any issue with you using another attribution medium what so ever.
Yeah it's complicated, but the nice thing is that allot of the websites at least use similar custom licensing schemes and they do use plain English.
Now as to a debugger, what do you mean by that, you mean like a C++ debugger? I know nothing about how you would use one of those or even where to get one? I can give you the error when I get it again and tell you the symptoms, but you'd have to hook me up with anything more complicated or at least tell me how to do it, I can't code worth shit but I can follow basic instructions like any good monkey LOL.
I would be freakin thrilled if it was a simple output error...