HTTP Error 500.19 - Internal Server Error
The requested page cannot be accessed because
the related configuration data for the page is invalid.
Dont you just hate it.. you ran everything by the book and it still doesn't work.. well you dont have to do much BizTalk before this is business as usual ;)
Anyway, in this combination hosting Bam on SharePoint 2010 Foundation, the SharePoint BAM portal is running .net 4.0
And the error happens because the BAM site is inheriting handlers, that are also installed in your BAM web.config. Hence the Duplicate message.
One solution is to manually outcomment the specific handlers:

And you will be back in business.
Best guess, is that the Biztalk 2010 release team didnt get to re-test installation and configuration with the latest releases of SharePointFoundation. Hence the BAM installation includes the above handlers.
Michael Høtoft
ee901fa9-8a2c-47ab-80ef-95c494a2a8b1|0|.0
BizTalk Server
BizTalk Server, BAM