erroneous

Containing an error; inaccurate.

His answer to the sum was erroneous.

An erroneous early Fox News report about the New Orleans terror attack is warping the political dialogue in the aftermath of the deadly rampage.

Derived from an error.

His conclusion was erroneous, since it was based on a false assumption.

Mistaken.

Her choice at the line-up proved to be erroneous, as she had only seen the mugger for an instant.

Wandering; erratic.

Deviating from the requirements of the law, but without a lack of legal authority, thus not illegal.

If, while having the power to act, one commits error in the exercise of that power, he acts erroneously.