Not all files copied to burn folders are showing up as alias files.

Question

I am trying to perform a very trivial function of burning JPEGS on my DVD.  I've done it tons of times with minimal issues.
However, recently, I have noticed a consistent issue in the burn folder:
When I try to place JPEGS from a master/original folder to a burn folder on my desktop, I notice that most all files will correctly be "alias" files (as expected).  However, there are a few (one or two) that will show up as JPEG files.  That JPEG file size is smaller than the original, which leads me to believe that it is having trouble making it an alias file.  When I click on that JPEG file in the burn folder, I get the following error "the file 'xyz.jpg' could not be opened.  It may be damaged or use a file format that preview doesn't recognize."  However, when I open that file from the origina source, it opens fine.
When I "get info" properties, I notice that in the general file information section, it does not show the original source location (as it does when looking at the alias "get info" properties.)
So what I have to do at this point is delete the false JPEG file image in the burn folder, and individually replace that with the file from the original source.  At that point, it makes it an alias file.
Although I found a work around to get files burned, I want to fix this so this does not happen when I am placing large amounts of files in burn folder.  As it is, I can no longer trust the burn folder and have to inspect it before I burn to make sure all files are alias files. 
Anybody experience this and have a way to fix this in the system?
Many of you probably are experiencing this, but if you are not checking your burn folder, it will just look like a corrupt file on your CD/DVD.
Thanks for your help.
Jeff

Answer 1

Hi all, thanks for your suggestions thus far.  Here is some additional information and initial answers to your comments.
I am still having the issue.  Currently, what I do is export full res files from my master RAWs using Aperture 3.  To do this, we create an export folder on desktop or any other specific storage location.  We then use the burn folders as a simple method to create an immediate backup DVD of the JPEGS.  As described above I am using the drag and drop technique currently to move images into the burn folder, as we have a few different labeled burn folders in our workflow. 
I am not using iPhoto at all for this process, as all of my images are managed with Aperture 3.  However, since the files/exports coming out of A3 seem to be fine, I am not currently questioning the integrity of the export.
I am going to try to use the burn folder technique from finder as BRB8910 suggests as an alternate method and report back on the outcome.
But Here is a revised issue of the initial stated problem:
I went back to my desktop to do some additional testing and tried a new condition...keeping the burn folder closed down.
On my desktop, I created a new burn folder called "burn tester 2".  I left it unopened and dragged the same master images from the same master folder directly into the folder collapsed down.  ANd guess what?  All the alias images seem to appear in the "Burn Tester 2" burn folder fine.
NOW, here is the newly discovered issue.  I removed the alias files in the "Burn Tester 2" Burn folder.  For my next test, I opened the empty burn folder.  So know I have an empty open burn folder window.  I then opened my master folder and highlighted all the master JPEG images and dragged them into the same "Burn Tester 2
burn folder that is now open.  Guess what?  The issue remains.  I will get some files that copy in as corrupt JPEG files along with mostly Alias files. 
I deleted the burn tester 2 burn folder all together, and recreated a third virgin burn folder and this time opened first.  when I dragged images to the freshly created and open burn foldder 3, I get the same issue.  When I delete the burn folder contents and collapse (close) the burn folder window, I then drag images to that burn folder 3 directly on the desktop (while closed), and then all the Alias files seem to drag in fine, with no JPEGs.
So it appears after my testing, I discovered that this issue only happens when I copy into a burn folder that is an open window.
I am just really confused as to why this is happening.
Hope this provides additional insight.  BTW:  Yes, I did reboot my system prior to retesting and I am using MAC OS 10.6.8 MacPro Quad Core with 8 GB RAM.
Jeff