That the city responds to an email claiming a carnival was or was not there 17 years ago means nothing.
You may have better luck calling.
Was it at a shopping center or a fairground or what?
Apparently the Phelps County Fair is held in Rolla (August 4-6 this year) so you might contact them.
You might also contact the fairground directly and see if they have other events besides the fair.
What did you lose?
Well they looked at the same photos I uploaded here and they told me there is no way that was in Rolla, Missouri, basically because the only two places that they would have carnivals or fairs would be either at the Lions Club Park or the Fairgrounds, and neither one of those places would have carnivals set up that close to the road (there is a 5th photo which I didn't upload here because it is very blurry and looks terrible, but a street is visible right next to the carnival rides in that photo).
I don't remember if it was next to a shopping center but what I do remember is that it was definitely not in a fenced in area or inside a park or anything like that.
I already looked into the Phelps County Fair prior to posting the thread on this forum, and it is like you say in August so it's not that. I haven't tried contacting the fairground directly but I will do that next.
What do you mean what did I lose?