Firefox hangs after r333650 (stagify linux-f10-flashplugin11)

[Lena at lena.kiev.ua]

8.4-RELEASE-p4 i386, ports tree and all ports freshly updated.
www/firefox hangs on (perhaps any) webpage with Flash.

Debug: using svn, I downgraded the directory
/usr/ports/www/linux-mplayer-plugin to r327776 (in order to de-delete
Makefile.npapi used previously by linux-f10-flashplugin11/Makefile),
downgraded www/linux-f10-flashplugin11 to r331411,
`portupgrade -f www/linux-f10-flashplugin11`, restarted Firefox -
Flash works OK, for example http://www.adobe.com/software/flash/about/

Then I updated www/linux-f10-flashplugin11 to the next revision r333650
("Stagify linux-f10-flashplayer. This makes all my ports STAGEDIR safe!"),
`portupgrade -f www/linux-f10-flashplugin11`, restarted Firefox,
then I go to a webpage with Flash - Firefox hangs for 90 sec or longer
(waits for something - doesn't eat CPU),
then a "Warning: Unresponsive script" pop-up may appear.
Flash doesn't play.

Then I downgrade www/linux-f10-flashplugin11 back to r331411,
`portupgrade -f www/linux-f10-flashplugin11` - Flash now works
even without Firefox restart.

May be, after stagifying the new packing list lacks some file?