I wanted to move my passwords from Opera to Chrome too. But what my experience has given me is to NEVER base yourself on company service to store your data : just watch Symbian, Opera like Opera Mail, and many others. It will maybe be the case of LastPass, later. Dropbox... Etc.
So what I have done, is download Web Pass Viewer which gave me all my passwords of Opera 12, and save them in a simple text file. As it is dangerous to do so, I have then hide the text file and renamed it, and crypted it with a very simple but hard to crack text file crypter.
Now, I save all my passwords in a text file. Just like in old times when people wrote their personnal things in a old book.