id3/tag.h
Code:
class ID3_CPP_EXPORT ID3_Tag
{
If you did carefully read my post on the previous page then i said you CAN'T use classes between compilers when using static compile (.dll)
So compile the full source into your project.
This means your makefile should compile all .c files of the id3lib OR use my previous example which is an example in C and not C++.
Closed source or not, i think you should learn about compilers, c++ and namemangling to fully understand why classes in dll's are bad.