Ah, I see - some proprietary raster format. No luck there.
As someone who develops a navigation software package, I'd like to note that:
1) If a user contacts me telling me they reinstalled their system and need a replacement license code, I send one to them. They paid for the right to use the application and that right had no time limit on it. (Admittedlyt, If a user will contact me for a new code once a week, I'll probably get a little bit suspicious)
2) User has a right to use the charts he paid for for as long as he wants. Your paper chart does not disintegrate and neither should electronic matter. There should be some notification to the fact that it is older than a specific period, but that's the extent of it. Whether it is legal or not, it is completely unethical to restrict access to properly purchased media.
That's my personal opinion, worth all of the money you paid for it
That said, this is why it is important to use charts in open formats, rather than proprietary ones - then no one can restrict your use of the media your honestly paid for.