Ajax Photo Album "requires a license file"

I use SEF Advace v4.2 (29.08.2005) with no problem -- probably should upgrade, but scared of losing my aliases.. anyway, that's not the issue today.

I just installed Ajax Photo Album (5 day trial) and get this message:

The encoded file /www/joomla/components/com_apa/sef_ext.php requires a license file ../com_sef/key.txt.

Is this because of a version conflict between the two products or something else?

Thanks for any advice!

Well, to answer myself, I updated to the latest version of SEF Advance and have not had this error message / problem.

Yes, the extension for AJAX Photo Album requires a newer version of SEF Advance.
If somebody doesn't want to upgrade though, he can just upload file key.txt found in new SEF Advance to its component directory.