I got this exact same error after installing NB6.5 and GF2.2, but it worked out-of-the-box with NB6.1 and GF2.1.
I resolved it by removing all settings other than these (in the Addition Properties tab of the Resources/JDBC/Connection Pools screen in the GF admin) for the connection pool: User, DatabaseName, Password, serverName, URL, portNumber.
I can't remember which, but I think one of the ones i removed had a value of 'off' (it related to security/SSL IIRC). I believe that removing that fixed it.
I consider this a bug in either the NB or GF distributions, or a version mismatch.
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