So so so....finally I have learnt to create a DLL in DEV C++ (Open src compiler with IDE)
Now I have also created a DLL in VC++ and I am trying to call the DLL in my DEV c++ EXE project. I have correctly specified the library file (.lib) of my vc++ DLL.
However from the same project i call one of my DEV C++ dlls and I am able to do that successfully..
I think the major suspect is the ".lib" file of the VC++ DLL. My dev C++ creates library files with extension ".a" which i refer to and run successfully..
Any idea what is going wrong???

There is no way to mix .lib and .dll files between different platforms and compilers.