It depends on what you mean by "civilian protesters"
The original claim as I understand it, that people gather in the cities to protest and were strafed and bombed by Gaddafi planes in mid to late feb. This, according to Russian military sources is false
http://www.youtube.com/watch?v=0_Upkqagf3o
However, if you mean by "civilian protesters" insurgents on the desert road between Ras Lanuf and Ajadibiyah, then it is true - although apparantly not very accurate - perhaps they didn't want to damage the road. They also bombed some ammunitions dumps.
So the original claim was false. But using aircraft in situations that everyone except NATO, Al Jazeera and the 10 members of the UN Security Council recognise as combat situations is true.