What should i do if someone accuse me of ninja ?

Ok i face this situation very often.

Every raid i lead. 1 or 2 ppl start calling me ninja for giving item to someone or watever reason.

Today i was leading TOC 25... top 5 winners would get Tokens and everyone rolled. One DK rolled 95, i m 100% sure he traded me his token.
But he started me accusing of being ninja that i didnt gave him token, and he is gonna report me.

I offered him that if he do live Video Skype call and show me his Bank + Bag + vendor buyback all at once... i give him my token ( i also won token). But he declined that he can only give me SS of his bag + bank (which i declined, coz he can SS bank while item in bag.. and SS bag while item in bank).

So wat should i do in these type of situation ?

And one more thing... Is it ok for Holy pala or Boomie to roll cloth item ? or not ?

I don't know how exactly ninja cases are investigated here, but I see tons of ninja bans every day. If I were you I'd trust the GMs judicial system, if you're really innocent you should not get banned unless someone actually modifies some evidence, like with photoshop or video editors. Even if you get banned you can file a ban appeal, but it's only worth doing if you're REALLY innocent, so you can pull a reverse uno card on that nasty evidence fabricator. If he refused to do the skype thing its probably because he's just pulling your leg or he's just mad in general. I always record my raids from start to finish to avoid such inconvenience.

To youe last question:

Check BiS lists for players. Generally speaking, if no one else needs that cloth item you can give it to anyone who can make little use of it. But first, it's always mages, lock and priests who roll for cloth.

Honestly, if I were you, I would simply start recording all of my raids.
If you like being a raid leader, and do this often, this is, in my books, 100% necessary. Start recording from the moment you /rw all the loot rules(if there are any), and only end the recording AFTER the loot was shared.
This way, if anyone accuses you of ninja'ing an item, you have full proof of doing nothing wrong.
As for your case specifically, there just isn't much you can do. Let's say the said individual reports you; without proof of him actually being ninja'd and you actually doing it, the GM's can't do anything about it.
If there wasn't any wrong-doing on your behalf, you shouldn't worry too much.