D and .lib files. C++/Other?

[Damien Gibson via Digitalmars-d-learn]

Well I ended up getting it to compile finally by adding extern 
"C" before the function imports on C++ side (Again i added the 
extern(C) to D side) however i still end up not being able to run 
the program as it keeps telling me:

0xC0000005: Access violation reading location 0x00000000

Ive been googling this for a while but can't seem to figure out 
what causes it aside from the general concensus being "Im trying 
to access a null pointer" but neither side of my code as far as i 
can tell actually attempts this... any ideas?