You can't directly. The file format has changed too much. You'll need to open it first with an intermediary version such as filemaker 3 to convert it to that format and then use filemaker 11 to open and convert that. The result may or may not require additional changes/updates before you can use the file as you are taking your file through a lot of changes.
An alternative to this is to open the file with filemaker 2, export the data as a tab delimitted file and then import this file into filemaker 11. That approach pulls in only the data and doesnot reproduce any layouts you may have in filemaker 2.
Here's a knowledgebase article on the process: