deleting a file

There are some steps here you may try.

You can't empty the Trash or move a file to the Trash

Since that didn't solve your question, I wonder if I something I figured out can help. I couldn't empty my trash because of files that I was unable to open, etc. Though I can't be sure its the problem you are having. I have VMWare fusion so I guess some of these files were somehow saved as Windows files. When I opened VMWare fusion and had my Windows Machine on, when I emptied my trash, all the files finally deleted completely. If for any reason you have a Windows machine on your computer with VMWare fusion, that could be the problem. Anyhow, in case someone else comes by and that is their problem, I thought it was worth sharing, but hope it helped you too.