Copied from another thread:
"I struggled to get ImgBurn to burn FLACs without dropping frames at the end of files. I was testing with a gapless live album and there were ticks between some of the songs. After exchanging messages with ImgBurn's author, I confirmed the problem was with the DirectShow filters I was using. Illiminable and CoreFLAC don't work right.
Fortunately this one does: DC-Bass Source Filter,
http://www.dsp-worx.de/?n=15. The CDR was verified by ImgBurn and had no audible gaps."
MadFlac is another choice in the future. It does not work at the moment but the author is working on it.