Desc:
   If JRE + FX 2.1 are installed and FX version is higher ( 6u32 + FX 2.1 b17 ) then jpi_version is 170_04 in about:plugins for FF/GC.
   But application/x-java-applet;jpi_version in registry is "160_32" under MozillaPlugins->@java.com/JavaPlugin,version=10.4.1->MimeTypes

   So if we request 1.6.0_32 via jpi_version applet is not loaded in FF/CG( "need to install plugin" is shown ), although JRE 6u32 is
   installed.

   For 1.6.0_32 classid all works as expected in IE if 6u32 and FX 2.1 are installed.

   See comments for more details.