After checking out a number of sites on the Net, it seems that most of the grammar pages say that adverbs of manner, like nicely, normally come after the verb. That may be true.
I find that it all depends on what I want to emphasize in the sentence. In the biomedical papers that I edit, I always change "as described previously" to "as previously described". Why? It sounds better to my ear because I put primary stress on the first syllable of previously when it comes before the verb, and seems to me to be the proper word order for what I consider a set phrase that should emphasize previously rather than described.
Most adverbs of manner can be placed before or after the verb. As Chris says in a comment, it slightly changes the emphasis and the rhythm of the sentence, not the meaning.
Whoever told you that the word order was incorrect was wrong. It's not incorrect; it's merely a personal preference, a matter of style, not grammar and not semantics.
I look at you all
See the love there that's sleeping
While my guitar gently weeps
The rhythm of the sentence is what's important in these lyrics. It's perhaps less important in a science paper, but I usually think about it when I edit.
Putting an adverb in the wrong place can change the meaning and focus of the sentence. I tend to ignore "rules" about adverb placement when I write and edit. I think about where each word belongs in each sentence in context, not in theory.
NOTE : "...but I think usually about it" changes the meaning of the sentence.