What is a lame event?

You need to provide context. When you ask a question such a this, post the sentence in which you have read the expression. The probable meaning here is that the event is uninspiring, or is not entertaining, or the event has a silly or unjustified basis.

Without context, it is impossible to say for certain. Generally, "lame" is used to mean unconvincing or unworthy. If i see movie with a plot which is not believable, i might say that i didn't enjoy the movie because the plot was lame.

The context is that an editor was going to a party where he was nominated the writer of the year. but he is worried about something.

That's not the context. That's your description of the context--it doesn't tell enough. Post the entire sentence, or the entire paragraph in which you read the usage, because otherwise we don't necessarily have enough information to give you a good answer.

I suspect the editor was suggesting that either the event itself was not going to be entertaining, or that the award was unjustified. But i can't say without reading the context.