The procedure entry point Error :(

[TheGreatCthulhu]

Yes, but, security is not an issue, it's not that they may be malicious, but rather that they are likely not built the same way from the source code, i.e. not produced under the same "rules", to put it that way. That is, even though they were made from the correct version of the source code, and implement all the right things, the game expects to access that functionality in a certain way, but the DLL is not providing it in that way, on the binary level.
This could happen if, say, Frictional Games used one compiler, but the DLL you've found on the net was created with another, or something along those lines.

If so, then they can't communicate with each other - and as a consequence programs that want to use them, but were produced under a different set or rules, won't work.