I have also the crash when I try to go on the Commander Tab.

I play Chaos and it's happen after I destroyed the orks. Does anyanyone have a solution ? It's very annoying ! I can't unlock my champions !

I just had the same issues.
After the 1st faction got defeated, I cannot access the commander menu or going through the 2nd faction stronghold mission without constant crashes.

I had the very same problem; I tried both setting the compatibility mode to Windows 98 and using the "4 Gb" patch. It works for me now; must have been one of the two... likely the patch, since there seems to be an issue with memory management.

Exactly; I found that out after applying the fix.
To be sure, I haven't finished the map yet, so I can't be 100% sure about the commander tab bug that has been reported above. I just hope I'm not in for an unpleasant surprise. So far I've been able to access the commander screen without hassle.

UPDATE: I defeated Chaos and the commander screen showed up no problem. Everything seems to be in working order.

UPDATE 2: I spoke too early. Indeed the game crashes whenever I try to access the commander screen directly. I even get a "BsSndRpt" message window with the "Unrecognized argument '40,000'." error message. But I don't know how to make use of that information.
And yet, I captured another enemy stronghold and there weren't any issues with the cutscenes, so at least the game is playable, since...
That's exactly how I'm gonna act from now on - luckily we have that alternative. I just hope the game doesn't crash if I earn a new piece of wargear and thus I'm redirected automatically to the commander screen after winning a battle. It didn't happen last time.

For me working solution is a run darkcrusade.exe in compatibility mode win 8

Played Chaos and game crashed seconds maybe 1 minute only on Space marine stronghold mission after orbital relay secondary objective.

Solution: Save game right when you get orbital relay objective. Rush to the objective with one unit (chaos lord in my case). It triggered reinforcements cutscene and after that no issues.

I suppose general issue will be in specific ingame trigger for overflow and rushing to next trigger "block" it.

Game is just badly coded, this and Soulstorm. A few suggestions have been proposed, the only semi reliable one is save near the end, turn all graphics and settings to minimum, finish the mission, turn them up again on next level.