With some help it looks like the issue is that the .lib files are compiled with MinGW (GCC), and PureBasic's default ASM backend uses MSVC's linker which can't read that object format. Try compiling with the C backend instead (pbcompilerc, or enable it in Compiler Options in the IDE) - it uses GCC internally so it reads the MinGW .lib files natively. The C backend is actually faster too since it gets GCC's optimizer.