firefox-8.0 and adobe-flash-plugin-10.0.0.525 - how to get it working?

[Lasse Hillerøe Petersen <lhp%toft-hp.dk@localhost>]

NetBSD i386 5.99.58, all sources recently checked out from CVS.
shangrila:~ $ pkg_info -a|grep -E 'flash|nspl|firef'
firefox-8.0         Web browser with support for extensions
nspluginwrapper-1.2.2nb10 Use Netscape compatible plugins from other platforms
libflashsupport-1.1 Additional Interface Support for Linux Flash Player
adobe-flash-plugin-10.0.0.525 Adobe Flash Player Browser plugin

shangrila:~ $ nspluginwrapper -l
/usr/pkg/lib/netscape/plugins/npwrapper.libflashplayer.so
 Original plugin: /usr/pkg/lib/netscape/plugins/libflashplayer.so
 Wrapper version string: 1.2.2
/usr/pkg/lib/netscape/plugins/npwrapper.libflashplayer.so
 Original plugin: /usr/pkg/lib/netscape/plugins/libflashplayer.so
 Wrapper version string: 1.2.2

shangrila:~ $ firefox
(process:8555): Gtk-WARNING **: Locale not supported by C library.
       Using the fallback 'C' locale.
*** NSPlugin Wrapper *** ERROR: NPP_Write() wait for reply: Connection closed
*** NSPlugin Wrapper ***
WARNING:(/source/pkgsrc/www/nspluginwrapper/work/nspluginwrapper-1.2.2/src/npw-wrapper.c:2235):invoke_NPP_DestroyStream:
assertion failed: (rpc_method_invoke_possible(plugin->connection))
*** NSPlugin Wrapper *** ERROR: NPObject 0xb900a0d8 is no longer valid!
*** NSPlugin Wrapper *** ERROR: NPObject 0xb900a0d8 is no longer valid!
*** NSPlugin Wrapper *** ERROR: NPObject 0xb900a0d8 is no longer valid!
*** NSPlugin Wrapper *** ERROR: NPObject 0xb900a0d8 is no longer valid!
*** NSPlugin Wrapper *** ERROR: NPObject 0xb900a0d8 is no longer valid!
*** NSPlugin Wrapper *** ERROR: NPObject 0xb900a0d8 is no longer valid!
*** NSPlugin Wrapper *** ERROR: NPObject 0xb900a0d8 is no longer valid!
*** NSPlugin Wrapper *** ERROR: NPObject 0xb900a0d8 is no longer valid!
*** NSPlugin Wrapper *** ERROR: NPObject 0xb900a0d8 is no longer valid!
*** NSPlugin Wrapper *** ERROR: NPObject 0xb900a0d8 is no longer valid!
*** NSPlugin Wrapper *** ERROR: NPObject 0xb900a0d8 is no longer valid!
*** NSPlugin Wrapper *** ERROR: NPObject 0xb900a0d8 is no longer valid!
*** NSPlugin Wrapper *** ERROR: NPObject 0xb900a0d8 is no longer valid!
*** NSPlugin Wrapper *** ERROR: NPObject 0xb900a0d8 is no longer valid!
*** NSPlugin Wrapper *** ERROR: NPObject 0xb900a0d8 is no longer valid!
*** NSPlugin Wrapper *** ERROR: NPObject 0xb900a0d8 is no longer valid!
*** NSPlugin Wrapper ***
WARNING:(/source/pkgsrc/www/nspluginwrapper/work/nspluginwrapper-1.2.2/src/npw-wrapper.c:1973):invoke_NPP_GetValue:
assertion failed: (rpc_method_invoke_possible(plugin->connection))

(process:13549): Gtk-WARNING **: Locale not supported by C library.
       Using the fallback 'C' locale.
*** NSPlugin Wrapper ***
WARNING:(/source/pkgsrc/www/nspluginwrapper/work/nspluginwrapper-1.2.2/src/npw-wrapper.c:1854):invoke_NPP_Destroy:
assertion failed: (rpc_method_invoke_possible(plugin->connection))
*** NSPlugin Wrapper *** ERROR: NPObject 0xb900a0d8 is no longer valid!
*** NSPlugin Wrapper *** ERROR: NPP_Write() wait for reply: Connection closed
*** NSPlugin Wrapper ***
WARNING:(/source/pkgsrc/www/nspluginwrapper/work/nspluginwrapper-1.2.2/src/npw-wrapper.c:2235):invoke_NPP_DestroyStream:
assertion failed: (rpc_method_invoke_possible(plugin->connection))
*** NSPlugin Wrapper *** ERROR: NPObject 0xb8b0d060 is no longer valid!
*** NSPlugin Wrapper *** ERROR: NPObject 0xb8b0d060 is no longer valid!
*** NSPlugin Wrapper *** ERROR: NPObject 0xb8b0d060 is no longer valid!
*** NSPlugin Wrapper *** ERROR: NPObject 0xb8b0d060 is no longer valid!
*** NSPlugin Wrapper *** ERROR: NPObject 0xb8b0d060 is no longer valid!
*** NSPlugin Wrapper *** ERROR: NPObject 0xb8b0d060 is no longer valid!
*** NSPlugin Wrapper *** ERROR: NPObject 0xb8b0d060 is no longer valid!
*** NSPlugin Wrapper *** ERROR: NPObject 0xb8b0d060 is no longer valid!
*** NSPlugin Wrapper *** ERROR: NPObject 0xb8b0d060 is no longer valid!
*** NSPlugin Wrapper *** ERROR: NPObject 0xb8b0d060 is no longer valid!
*** NSPlugin Wrapper *** ERROR: NPObject 0xb8b0d060 is no longer valid!
*** NSPlugin Wrapper *** ERROR: NPObject 0xb8b0d060 is no longer valid!
*** NSPlugin Wrapper *** ERROR: NPObject 0xb8b0d060 is no longer valid!
*** NSPlugin Wrapper *** ERROR: NPObject 0xb8b0d060 is no longer valid!
*** NSPlugin Wrapper *** ERROR: NPObject 0xb8b0d060 is no longer valid!
*** NSPlugin Wrapper *** ERROR: NPObject 0xb8b0d060 is no longer valid!
*** NSPlugin Wrapper ***
WARNING:(/source/pkgsrc/www/nspluginwrapper/work/nspluginwrapper-1.2.2/src/npw-wrapper.c:1854):invoke_NPP_Destroy:
assertion failed: (rpc_method_invoke_possible(plugin->connection))
*** NSPlugin Wrapper *** ERROR: NPObject 0xb8b0d060 is no longer valid!

A ps aux shows something that may not necessarily be important, but
still makes me wonder:
lhp     26187  0.0  0.9  52156 19628 ttyp6  Sl+   3:59PM    0:00.15
/usr/pkg/lib/xulrunner/plugin-container /usr/pkg/lib/netsc@pe/p

Where did that netsc@pe come from? There is no such directory in /usr/pkg/lib?

I hope someone out there who has made this to a working state, could
share a tip or two... either how to make it work step by step, or how
to debug this problem. (Suggestions to switch to emulated Linux
firefox-bin are not necessary, I will probably go in that direction if
I don't have any luck, but only as a last resort.)

/Lasse