Well I couldnt enable my blood effect ingame so i decided to do it manualy, heres how.
1. go to your Combar Arms folder.
2. go into the "Profiles" folder.
3. click on the text document that says "player".
4. scroll down in that document till u see the [Game] category.
5. then in that category youll see "Gore = 0" change that to "Gore = 1".
6. save the document, load up CA and you have blood effect on.
Thank me/lvl my habamon if i helped :S