Plugin DLL extraction not happening on Windows 98

I have an installer that calls a simple plugin DLL function in my .onInit function. This works just fine on Windows XP but doesn't on Windows 98.

I've noticed on Windows 98 that the $PLUGINSDIR does get initialized (gets created in WINDOWS\Temp) but that the actual plugin DLL never gets extracted into the $PLUGINSDIR directory.

Does anyone have any idea where I should look next to locate the problem? Any help is greatly appreciated.

Please include some examples and which version of NSIS you were using.