I have fought with this for a week now and finally found a solution.
The error was when a user would attempt to create a new Layer2.de SharePoint Business Data List Connector in a SharePoint 2010 list they would recieve an OLEDB Unspecified Error.
Server 2008 R2 with SharePoint 2010
The problem is related to a security setting on the temp folder - but which one and where???
c:\users\temp.domain\appdata\local\temp
I added the Everyone group to the read/write/modify security on the temp folder above and it WORKS!!
This does grant all users of the server full access to the appdata temp folder so it is not a security best practice - but until I can find a better solution to this problem it works now.
