I've had this exact same problem. As far as I can tell the dreadlords are broken on this level. They never build any ships or do anything. I have tried to invade the planet eveyway possible. I have almost maxed out tech(I qualify for the tech victory), I control every other planet in the galaxy, and I have four spys (most possible) in dreadloard society. I have sent rediculous amounts of troops at the planet. I have used tidal warfare, gas warfare, information warfare, traditional warfare, mass drivers, core destruction. Nothing ever works. I built a fleet of five special custom troop transport ships that can hold 14000 troops each and sent that to invade the planet. All my troops died and not one of the twenty dreadlord troops died.

Nothing works. What do I (we/players) do?

I too have this problem. Most disappointing.

I made several fleets of 5 huge transports that held 7,000 soldiers each (35k troops per fleet) and invaded the planet each of the invasion types (standard, mass drivers, gas, etc.) in turn. Even after dumping ~150k soldiers on them, not one of their 20 soldiers died.

I am playing on cakewalk. I did notice in an earlier mission that the game was easier to beat on harder settings because your allies help out some. I am going to try to restart this mission on a hader setting to see if that helps.

Same thing here. Dread Lords do nothing, and I get this wierd number like -2400000 on my side of the odds when trying to invade the planet. The planet is impossible to take! C'mon Brad or somebody at stardock tell us how to fix this. I paid money for this game I'd at least like to be able to complete the campaign.

Ridiculous...

I'm having the same problem as well with the Ultimate Edition, v2.0.2. I'm very disappointed with this. Normally these bugs like this one and the Apocalypse one are resolved long before a so-called Ultimate edition comes out.