Go into the folder where your RO files are. Directly in there (not in a subfolder), look for a file called "neoncube.file" you can open it with notepad or other text editting software.
Change the number inside to 280 save, then relaunch the patcher.
You'll be missing something from the May patch, which may prompt you to crash on something. Go back to neoncube file that Panda mentioned, and lower the number by 1. Save, then try patching again. See if the patcher succeeds in fetching the problematic file this time.
I've been getting this a lot too. Usually closing and relaunching the patcher works for me. It's hard for it to be a conflict with another server since heRO's the only one in the destination folder(s)
The Oka Compendium: A glorified record of my alt-a-holic-ism. May or may not be up to date at any given point.