I don’t want to assume your preferences or what you may have already done but here is a reminder.
“Your argument is wrong because we are in 2014 and not the 1950s.”
Depending on what this is referring to, it may be a number of fallacies or none at all.
Wikipedia has a long List of fallacies which I think goes a bit overboard. This site seems to have a more concise list of Logical Fallacies.
It is important to keep in mind whether or not the initial argument is fallacious. If I argue: Something is true of 1950 therefore it is true of 2014. Something that is true in the 1950’s may be true in 2014 but, I believe, this might be a Falacy of composition. Something that is true of one year or group of years is not necessarily true of all years. The initial argument may commit a formal fallacy, such as affirming the consequent. People went to the movies in 1950, I just went to the movies, therefore it’s 1950. I think in such a case, “Your argument is wrong because we are in 2014 and not the 1950s.” would be valid.
In the 1950’s communist rebels overthrew the Cuban government.
There are communist rebels in the U.S.
Therefore communist rebels might try to overthrow the U.S. government.
In this case, “Your argument is wrong because we are in 2014 and not the 1950s.” might well be described as an Ignoratio elenchi. I admit, I have never come across this term before but, where arguments of refutation are concerned, it seems to occur quite frequently.
Regarding a Time Fallacy. You might find either an Appeal to novelty or an Appeal to antiquity is taking place. For a slightly different take on appeal to novelty take a look at Chronological snobbery.
Do not take my response as authoritative. I am trying to learn by doing sort of thing. So that professor Casey can approve or critique my understanding of this subject. I hope this was, at least, helpful.