Your sentence is correct. I went to the current issue of The Economist, looked up the first article I saw about English literature, and found two similar constructions. Here’s one (emphasis added):
The Economist, reviewing it in 1847, argued that it was “perfectly fresh and lifelike” and, as such, “far removed from the namby pamby stuff of which fashionable novels are made”
It has been completely acceptable in the most formal English for centuries, to wit:
And God blessed them, saying, Be fruitful, and multiply, and fill the waters in the seas, and let fowl multiply in the earth.
Or more recently:
We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness. That to secure these rights, Governments are instituted among Men, deriving their just powers from the consent of the governed [....]
(And if your instructor accepts those, you get to start sentences with conjunctions. Also to write sentence fragments.)
Why is it getting marked as incorrect? It might be a hypercorrection, like how I’ve had some people try to convince me that it’s always bad style or even bad grammar to use the word was. I’ve seen the claim that the construction you’re talking about is often misused, and that sometimes leads to the misunderstanding that there is a rule against it.
Let’s look at a sentence that some would accept as correct grammar and some would not: “He started his car, backing it out of the driveway.”
One usage that some people flag as an error is using this construction for two actions that are not simultaneous. A driver first starts the car, then backs it out of the driveway; he was not backing it out of the driveway while he started the car. Others would accept this when the action in the simple past tense occurs immediately before the one that gets the present participle, as in this example. It is at the very least a common idiom. Fewer would accept, “She married him, divorcing seven years later,” as correct.
We see another pitfall with the sentence “He started his car, backing it out of the driveway,” when we compare it to, “She swerved out of the path of the car backing out of the driveway.” The clause backing it out of the driveway modifies he, but the noun immediately before it is car, so it is arguably a misplaced modifier. Using commas the way I just did can fix that ambiguity, but writers don’t do so consistently.
If I say, “I went up to the girl singing that song,” is she singing or am I? This construction, where the present participle comes after a main clause containing more than one noun, can be ambiguous about which noun the phrase is modifying and some people think you should always avoid it. Therefore, some sources say that “Singing that song, I went up to the girl,” is correct, but not the other way around.
Either might be the origin of your instructor’s belief that this usage is always wrong.
(I added an even earlier example here, at one point, but on a closer reading, I no longer think it is grammatically parallel.)