We need a lot more information to help you any further. Is the CFB standalone, or plugin version? If plugin, what version of Eclipse? What version of Subclipse is currently installed? How was the existing Subclipse originally installed (using Eclipse installation options or manually by moving files into the Eclipse folder tree)?
When you tried to do the upgrade using the "Check for Updates" feature, what exactly happened? We need a detailed step by step description of what you tried, along with the exact text of any error messages received. Saying you tried it to no avail doesn't give us any clue as to how or why it failed.
