first please use punctuation in your post so i can tell when one sentence ends and the next sentence begins.
as i understand, the unrecognized disc's are backup's. your standalone dvd player is device showing "unrecognized disc". does not matter which computer you use to create the backups, neither disc will play. you were, at one time, able to create backups with your desktop but now these backups do not work, now that dvdfab has been installed. you do not think the problem could be the blank media because you are using the same brand which you have always used.
do you have other burning programs or do you use only dvdfab gold? can you post a burn log please?