Hmmm... I assume that the line number in the error message refers to the "org" line? Strange! "org" is recognized in "-f bin" only. If you think you're assembling in binary format, you probably are - it's the default - but this sounds like what you'd get in some other output format.
The only thing I can suggest is to maybe post a little more of the exact code you're (not) assembling, and the exact command line you're giving Nasm. Should be something like "nasm -f bin -o myfile.com myfile.asm". Just "nasm -o myfile.com myfile.asm" ought to work, too. The more I think about it, the more it seems like it "must" be a "command line problem" of some sort!
Nasm *will* produce .com files - honest! - so don't give up until you've solved it!
Best,
Frank
