OK.. Co-OP was designed for Gamespy Arcade use, however it can be done in a single player fashion...
Launch the Configuration utility from the start menu programs folder and configure the script, then when done and it is closed, launch SFC OP or EAW, and click multiplayer mode.. then look at bottom right corner and Click host.. select Co-Op Ace, select map size, set era and BPV, then submit, you will go into a screen that has 6 slots.. all slots will be allied by this script so you can set up AI's to go in with you.. you can set yourself and each AI with 1 to 3 ships each.. all of which you choose manually, just remember what you set your script config for in difficulty.. as such if your difficulty is 1.3 then that is your BPV, plus your AI Wingmen BPV total * 1.3... the game gets that ammount of BPV to build the enemy fleet to go against you.. this includes loadout BPV.. when you launch game, enemies will be either out of sensor range or they will be at the edge of sensor range and all the enemy will come at you as a fleet at once..
anyhow, that is how you get into the script in single player.. internet Connection is not needed..
However you can play all the Gamespy Skirmish scripts this way.. or on Gamespy Arcade, or through TCP/IP connection, or on a Lan connection... just remember that if you are doing it in a single player fashion, you will need to set up AI opponents manually using the Ai toggle and select their ships manually
Hope that this helps.