What does it also say? When there's a build error (assembly error), the assembler will usually display information about the error, such as: The source file directory the error is in. The line number in that source file the error is on. What the error is (sometimes not 100% specific, but generally). I would argue approximately 90% of all errors are "branch out of range" for branches that are... out of range, or "illegal value" for instructions that reference a relative address which is simply too far away. The problem is, we don't know. Simply put, let us know what that error is, either paste the text or even a screenshot of the CMD window if you have to, and we'll explain what the error is, why it happened, and how to fix it so you know in future.