Here's the run down, to decompile a "protected" map you need two things:
BSP file that doesn't crash vmex
Vmex that doesn't quit on job every time it detects signs of "protection" (special textures, brushes of specific sizes etc.)
To solve first problem you need to remove malicious key entries from entities.. Usually there's only one, it's called no_decomp 1. You can remove it with entspy utility
Get EntSpy utility, open BSP file in it, if you see nodecomp key anywhere just delete and resave BSP. If you don't see it open BSP file in notepad, search for nodecomp, if you find it, note value of "classname". Go back to entSpy and find entity with this name, it should have no_decomp inside.
Normally this is as far as anti idiot protection goes.
If author really doesn't want his levels to be decompiled, they put prefabs in, that vmex can detect. Hacked vmex skips it.
Note that even hacked vmex can't decompile a map with nodecomp in it :)). So you have to use entSpy still. Wierd, right? Actually there is a very logical explanation for it. You see nodecomp is an artificially added key, it has no business inside bsp file. Bsp file knows how many keys every entity has, so even if you add a totally random key into any entity it won't break the game it just won't notice it. However vmex is coded in such way so that it crashes every time there's a mismatch between number of keys STORED and number of keys EXPECTED. In particular vmex 0.98 crashes because of array overflow.. or something like that...
Try it, add nodecomp and it won't even tell you it's protected it'll just crash. So DJuke, nodecomp is not your problem, you need a hacked vmex. I have one or you can google it, there's another one out there.
I've put together small pack, it has vmex modified source code and entspy, enjoy: http://depositfiles.com/files/4m6mkpwon
To the rest of you moralists and greedy mappers, i have a treat for you too.
IF YOU REALLY WANT TO PROTECT YOUR MAPS:
get entSpy and add random keys to any entities. Try to use key names that make sense. It will take ages for anyone to figure out what keys are preventing a map from being decompiled. nodecomp was just an arbitrary key name it could be anything, like notheft, f*ck_you or this_will_cause_a_crash_hahaha
And.. make a copy, will you.. i tried it and it didn't break my map, but i can't guaranty anything.
Merry Xmas, and happy decom... learning.
Bananite