Incorrect block size and generated iso images

I tried the search, couldn't really find anything, so hence the new post. (this is not a n00b post, I know exactly how to make backups, so please don't tell me to make an .iso and burn, etc etc) This is me trying to get stuff to work for my own edification.
I copied a smallish game that I own to my HDD - not in .iso format, just straight dragged and dropped the files and folders onto my HDD. So all the files and folders are sitting on my HDD, and now I want to make an .iso out of them which I could boot on my PS2.
I opened CD DVD Gen 1.50, dragged and dropped first the System.cnf, then the SLUS, then the folders in alphabetical order into the CD DVD Gen folder. I entered the SLUS info under the "Volume" tab (in this case it was Super Bust a Move, and the SLUS was 20115). (Oh, it's a CD based game, so I picked the option to make a Master CD-ROM, not DVD ROM). Hit Record, clicked past the two error messages, then I picked "Export Image" under File. Then, I opened command prompt, typed in "copy /b bust.000 bust.iso" to make the iso file. After that long ass winded post, here's my problem. When I try to burn the .iso with Nero, it tells me the block size does not correspond, do I want to correct or fix it. DAMN.
I tried to ingore it after trying all possible options, and the PS2 recognizes it as a PS2 disk (blue bottomed in the Browser screen, so it made a Master CD-ROM), but it does not boot!!!! Argh.
Any thoughts - what did I do wrong.
For more info, I followed the guide somewhat on this guys page.

http://homepages.ihug.co.nz/~cbjull/DVD9toDVD5.htm