with or without admin rights????

this is the way a iso image is built.
when building an iso image first the structure is built. meaning how many files are inside, the folder structure, the !filesize! and all other attributes.
for this reason even when you get an error while building the image (as you got while adding the sam file) the files will be present with their original filesize inside that image, but actually the data inside that files is completely missing or messed up. so the sam file you got inside the isoimage will have the original filesize and all its attributes but not the data inside it.
you can validate it by inserting one of your failed backups (where burning process interupted after few %)and open them with isobuster for example.
you will see it will show all files with their original filesize but infact the files aren't on the CD only their attributes are.
keep that in mind when working with images, if you can see a file its not sure its actually there!
so your copied sam file is most likely worth nothing, sorry

to validate if data is present inside your samfile just open it with a hexeditor I'm almost 100% sure you will not see more than empty fields


/edit
what I'm talking about is the The ISO 9660 format.
Its specifying the logical format for files and directories on a CD-ROM. It provides a cross-platform format for storing filenames and directories which restricts the characters used to ensure all CD-ROM drives of all ages can read a data disc.
this information is first written into an IMAGE so every ISO 9660 compatible Drive can read the image. This information contains the file and folderstructure (also the filesize).
So after the sam file got analyzed and the proper ISO 9660 information got written into the image it THEN tries to access the samfile and at this point your image creaton will fail. it looks like the file is there but is not.
hope you understood the little information about iso file structures