Well, the link I posted will work if you are logged in. This is a bug in the forum that the paging is different for users logged in or users not logged in. Sorry about that!
Even, if you do not encrypt your file, the passwords are still "encrypted" and if you have a password defined on all your machines it will take a while. You could create a backup of your file and try to encrypt the entire file with a master password - just click on the document in the tree, go to properties and set the option to encryot the whole file. Specify a master password and try to open/save your document. It should be much faster.
cheers,
Stefan