The problem was that there was (and still is to some extent) some confusion about how much of their debt was implicitly or explicitly insured by the government.

The problem was that there was (and still is to some extent) some confusion about how much of their debt was implicitly or explicitly insured by the government. And yes, I realize how ridiculous this sounds but these things (billions of dollars in obligations) really were completely up in the air, partly due to crap EU legislation.