Strange question about Dev-C++ 5.0 beta

I use Microsoft Visual studio in school for programming in school and I used Dev-C++ 4 on my Sisters computer, now to the question I tried to use Dev-C++ 5.0 beta on my own computer, I know it is beta and what that means, but I still find it strange that the code that worked liked a charm in microsoft visual studio (well I used a program in MS-Dos to compile it since it still is tiny non-windows program) doesn't compile in Dev-C++ 5.0 beta. Is it "stricter" on the code, meaning that my code is a bit sloppy and I just happen to get away with it in the other programs or what is the deal with it. If it was only the fact that it is beta that verision wouldn't be particular useful IMHO. Anyone have any ideas about this? If you want to see example code I will dig some up, I'm in the middle of transfering my files from my old computer to my new and due to lack of time haven't gotten it organized.