With debug level at 5 the plugin folder of MobilePhone.net still never gets a debug file this would usually suggest it never starts loading. "31/03/2010 10:35:54 PM: Plugin Manager: loading Global Plugins...
31/03/2010 10:35:54 PM: Plugin Manager: Plugin Found: MobilePhone(.NET) plugin found but will be unable to create (most likely NOT registered)[skipped]."
I've got Windows 7 x86 loaded as well and will be testing this shortly on that one.
I've tested on my Windows 7 x86 on the same machine and I get the same issue. Attempted registering the dll via the regasm .... /codebase and no luck. Has this plugin been tested on Windows 7?