Just managed to successfully get my posts from Blogger into DCT.
Read a post suggesting using a new temp WordPress blog which can import directly from Blogger. Then export, then use the Import tool in the Settings page of BlogEngine.Net (which launches a ClickOnce app). Although in retrospect I wonder if just pointing the Importer to the Blogger RSS feed might have made the WordPress step unnecessary.
There is a caveat in that comments are not imported - also did not attempt images\files import.