ok, either i am stupid or there are two things that are still not clear here:
1) is this for BeOS, Linux or something else? the question says BeOS in it, and all the answers seem to be for *IX systems, is BeOS one of them? i thought not. Please clarify.
2) What are you actually trying to do, Mr X? the URL you quote doesn't appear to work, and the phrase "write ISO file to hdd" does not, in my opinion, describe the action required sufficiently to provide an answer. It's not even a properly formed question, or in fact a sentence of any kind.