The paintball2_alpha3.zip file you have requested: Modifications / Paintball / Paintball 2.0 Alpha build003 Full Standalone - 19.65mb is not available. Perhaps try browsing all files for the game Quake 2 and upload any files you want to share or are missing. This is the only information we could locate:
standalone version of Paintball2. Extract to c: or c:games (or wherever you want, really).