The close votes and the reason (already resolved in comments) are not a flaw of the question.
Sometimes it may be ok to close a question with that reason (such if the solution comment refers to a simple typo or an outdated TeX installation), the fact that the solution was decided to be posted as a comment instead of being an answer may indicate it.
But, like here, sometimes a solution is just an unconfirmed guess and so posted as a comment. At occasions like this, it's good to
- ping the comment writer and ask him to turn the comment into an
- or post an answer with the solution, with attribution to the
comment writer (and then choosing community wiki status is common, to not earn reputation for just copying the solution into an answer)
The review queue process, that includes badges rewards for reviewers, unfortunately speeds up voting so 1. can be slower than getting close votes coming in. Note, your question also got 3 "keep open" votes in the review process.
You did good as you did 2. and posted the solution as the answer and accepted it. An improvement would be adding attribution to Marcel, then all is well documented and we can clean up the comments so the solution is clearly visible without distractions.
We had such questions already here, so here are earlier discussions on that topic: