I don't know this wallet and the address looks suspicious, so be warned (I'm a Nxt community member but not an expert - it may be actually trustworthy, but I don't know.).
On
http://nxt.org, the official NXT web site, there are only two online wallets linked (use them at your own risk!):
You may be better with them than with this "unknown" web wallet.
But I would
highly recommend you to install your own client on your computer. NXT's client is very easy to use actually. The only problem is that you will have to download the whole blockchain, that can take some hours as NXT is already more than two years old.
