Yeah, let's not be reviving two-year-old threads from here on out.
Mike, if the previous advice didn't help, typing in "
www.volition-inc.com" directly should work to activate cheats just fine in FS1; make sure you're hitting each key distinctly as you type it in, and don't hit anything else in-between letters. However, as has been indicated, you won't be able to advance in the campaign with cheats enabled (unless the trick that terran_emperor mentioned works). It's been a very long time since I played this mission, but I seem to recall focusing on disabling the Anvil with a dual Harbinger round first, then getting myself on protecting one of the Omegas (usually Omega 2, since that seemed to take the most damage). Try to get one wing on the transport you're not guarding, and get one or two additional ships on the one you are if you need them. Order everyone else to ignore the Anvil for the moment and engage the enemy fighters. If you get the chance, taking out the Anvil's weapons subsystem might be a decent idea; if not, at least try to take out any of its turrets that are firing on the transports. You should be able to sneak them both by with some trial and error. The
Wiki page on the mission contains some additional advice.