Why can't I empty Trash ("error code 8003")?

I'm unable to empty the Trash (Mac OS 10.8.6), which apparently has about 30,000 items in it (I was trying to make room on a 64GB flash drive). I get a message saying, "The operation can't be completed because an unexpected error occurred (error code 8003)." I don't know what error code 8003 means.

So far, I've tried this: After looking at Apple article <You can't empty the Trash or move a file to the Trash - Apple Support> , I (1) tried holding down the Option key while selecting "empty Trash." (2) When that didn't work, I tried holding down Control and Option while selecting "empty Trash," but the same message came up. (3) After a Google search, I was steered to an X-Lab article that described using Terminal for an operation that might solve my problem but I'm pretty low tech and I'm not comfortable attempting an operation with Terminal that might inadvertently delete my hard drive!

Apparently the problem isn't locked files, unless that's what error code 8003 means, but if so, is there a way to identify the files that are locked and either remove them to the Desktop or order the Finder to empty the Trash anyway? If not, does anyone know how I can solve the problem without resorting to the dangerous Terminal operation (which I'm not sure will solve the problem anyway)? Thanks!