I am using Vc++(2012) with allegro 5.0.7. and following this link for tutorials.
I get assertion Failed error when I compiled the code present at the above given link. Here is a snapshot of my error.
You are trying to use a null bitmap. The most common reason is you are running your program from a directory that you are not expecting, causing your relative paths to fail.
Read and follow the advice of this article to solve the issue.