The maps & airfields are not the problem, it's the exploding spawning aircraft which came with 4.101 if there is a false regiment or loadout entry in the mission file.
DCG uses allpayloads.dcg to assign the loadouts for a mission, so if there is an error here it will still get put into the mission with the above result.
The master reference for allpayloads is normally weapons_rus.properties, which has the 'raw' entries and the often more comprehensible text overlays.
However, the problem has been that the weapons file in DBW is full of placeholder entries for loadouts which are (as yet?) not there, if you look at the included copy of the weapons file you can see for example that the Spitfire Vs have entries for drop tanks, but in game there is only default or none; if these entries are then carried over into the DCG allpayloads file they will also go into the mission file if you select that loadout in DCG, and then we get the exploding spawns again.
Some planes like the Seafire 3s have doubled entries in game, and some weapons entries are also longer than the 20 character DCG limit, but I should have got all of those.
Getting the correct loadout entries is further complicated by the fact that DBW is built on top of UP3, which has a weapons file (actually all config files) built into one of the SFS files, so you can't disable the DBW weapons file and see the raw loadouts in QMB, you always get the UP entries, which also seem to have some errors.
Nobody ever pays much attention to weapons_rus.properties as it's seen as just cosmetic, but here it's a real problem, trying to eliminate all the placeholders and/or errors is an ongoing process currently, I keep finding another one, which is probably the problem you're having now.
One or more planes used in that campaign (in this case Normandy) probably have a loadout entry which isn't implemented in game, producing the error.
The way around this is to check for which one it is, make a copy of the mission file for reference and then change all the loadouts in the original misison file to default, and the mission should now load and play, but with no loadouts.
You can then look at the original mission file and add one of the loadouts back in, load and test. Boom means that's a bad loadout, and needs to be reported, normal start means the loadout is OK and it must be a different one.
A long and wearisome process, but that's troubleshooting, and why this is still a WIP, it won't go to version 1.0 until this is finally sorted out, but shouldn't normally be a problem in the first place.
It is of course also possible that the original DCG mission files are referencing a squadron which isn't in DBW, some of them were changed in 4.101, but the DCG mission files should be good for 4.101 as far as I know, Paul would know for sure; to fix this all the DCG campaign mission files would have to be updated to 4.101 regiments.
You can check this by opening the console after your planes go boom, scroll with Page Up/Down and look for an error saying can't find regiment or loadout xxx.
Forgotten Countries (standard) should deal with this, as CirX put all the changed regiments back in original form, but maybe this needs to be confirmed.
I covered this problem in some detail in the original post, where all loadouts were set to default for testing, but looks like I took the explanations down too early, still, new version coming up so things are improving, hang on and maybe I already fixed it, but we still really need a definitive weapons file with no errors and no placeholders, but there probably isn't one and it would would be a huge job to make one, for which I'd have to ask CirX if he has the time, and this is my shit and not his responsibility, but just reporting errors is always helpful.
UPDATE
Tried all three Normandy campaigns, only to find it's the last one, 44, that seems to have the problem;
The napalm loadout for the P38s is wrong, instead of 2x175napalm (as in the weapons file) it's 2x154Napalm (case sensitive).
Had to use a test mission to read out the loadout, Normandy 44 campaign then loaded fine (but that doesn't mean there aren't any more hiding in there somewhere).
Fixed in new, coming, version.
If anyone finds any more bad loadouts, report it here so it can be fixed, post the mission so I can check it, or just say which campaign and I'll look into it.
Also noticed the stock campaigns are badly in need of updating, there's so much more we could do with DBW versions, correct planes, weather, AA & C&C from CY6, new maps for some campaigns like Normandy would be a big project though. However, first get these files working, then there's my BoB campaign, or redo the stock ones, have to ask Paul when the forum is back up.