The reason why some of the files are blocking the trash from emptying is because of specific ".app" files from third party companies like Adobe products. Not the user files or the various help documents but instead the actual mother program. Here's how to fix this problem:
1) remove from the trash all the actual software programs like Photoshop, InDesign, DreamWeaver and so on and put them on the desktop.
2) Command "I" (info) and when the dialog box opens go to the "Name & Extension" text box and remove the ".app" from the software name. Example: Photoshop.app change to Photoshop.
3) the program icon will change to a "folder icon".
4) put the folder icon back into the trash and you should be able to now empty the trash.
If you continue to get the error code 8003 it's because you may still have one or more software programs in the trash that needs to go through this process. Remember - it's not the user files or help documents or supporting files that is causing this but instead the "actual product programs".
JKai