Local installation not working

[Fabian Lenzen]

Hi,

I am currently trying to start developing an extension for Thunderbird,
hence I tried to follow this [1] guide. My Problem is step 6, installing
the extension locally. My extension is placed in c:\serialletter\.
Actually, this is the directory that contains the chrome.manifest and
the install.rdf file. My install.rdf is this [2]

I placed a file named serial...@fabianlenzen.de -- i. e. the id named
in the install.rdf -- in %APPDATA%\Thunderbird\Profiles\<1>\extensions
that contains only "c:\serialletter\", without the quotation marks. No
Spaces, no newlines, no BOM. <1> means the only profile that is placed
in that directory.

I think that should be all to make my newly developed extension run in
Thunderbird, but when I restart TB, the overlay is not applied, and the
extension does not show up in TB's add-on dialog. I have no idea how to
fix this, can anyone help me?

My system: Windows XP SP3, Thunderbird/3.1.6

Best regards,
Fabian.

[1]
https://developer.mozilla.org/en/Extensions/Thunderbird/Building_a_Thunderbird_extension
[2] http://pastebin.com/wUgtRJvc