REGXPCOM was added to the plugin at the insistence of both Netscape and the Netscape group here at Sun. This support is not only unnessesary it is actually harmfull to the plugins ability to be compatable with different releases of Netscape.
One example of this is the inability of the plugin to work with a GCC V3.X compiled Netscape/Mozilla. This is due to the need to use static C++ symbols to support browser that used early version of the REGXPCOM interface (such as 6.2.1).
All REGXPCOM code should be stripped from the plugin source base.