This bug was found while using FishEye/Crucible 2.7.11
I also added a comment in closed bug CRUC-612 because it was the only one that showed up for me when I did a search on the error string.

I started a new review and uploaded a pre-commit patch with 5 files. I made comments on 4/5 files. None of the invited reviewers had yet looked at the review. I later uploaded an updated pre-commit patch and wanted to remove the original patch as none of the reviewers had yet looked at the review. I could only remove the one file with no existing comments. I then deleted all comments. I, as the review creator, was the only one who had yet made comments or read them. When I again tried to remove the files, I could remove some of the files that previously had comments, but not others. The error I received was "Could not remove ... as it has comments." where ... contained the path to the file. This error continues to persist even after coming back the next day.