We've seen a few reports, recently, in AdSense Help Forum: Blogger / Host Partners - and in Blogger Help Forum: Get Help with an Issue , that refer to a mysterious error condition. Error 500 "Internal Server Error". Blogger Support has been diagnosing this problem, for a while, using a series of bX codes - and the codes thrown by this condition seem to change, from day to day. The last time Blogger Support provided any description of the problem - or guidance how to solve the problem, they made general mention of "corrupt templates".
What Blogger won't tell you