You need to install CLEO 4 (or lastest version) to do this.

After install CLEO, open "CLEO" folder, and drag all files into "CLEO" folder

Open "models" folder, select all three files:
effects.fxp
effectsPC.txd
particle.txd
Then drag into game folder/models, and click "replace"

-> if you not doing this, you with not able to see flames.