=D Good news, I deal with a lot of Japanese government/court documents. They make me hate life in general, but that's another story for another time.
It's either a document/form number (think the tax documents, every single form has a number so you can research by form) OR a document number for the individual report (kinda like when you call up customer service, they give you a number so they can research your problem in the future).
I'm guessing it's a report number. It reads almost exactly like Japanese litigation documents.
58 General Affairs HQ, (e), No. 34
Does that fit in with the context?