Jierbe31's translation is actually more accurate except it might be simpler just to write "Except as otherwise noted, the information contained herein is given as of March 30, 2008."If I was translating this into English, I would say something like: "unless otherwise specifically indicated, the information given/provided in the circular is dated 31st..."
I'm not sure if this clarification helps, but "donnée en date du 31 mars" is not a term that means "dated on March 31". Rather, the meaning of the term, as commonly meant in many legal documents, simply indicates that the information provided was/is current as of the date indicated. Thus, contracts or agreements or press releases can be "dated" on a certain date. But, collecting and presenting information in a document is more appropriately described as having been provided "as of" a certain date.
I'm really not sure that clarifies anything. And, while I agree that "is given at the date of" is not correct, there is an obvious and clear difference between information that is "dated March 1" and information that is provided "as of March 1". Since it appears to be a legal document according to Bogdan76 , the difference is indeed important in order to obtain a proper translation.Let me put it this way for the sake of clarification for those looking later. I'm not a lawyer, and perhaps somebody who knows more about legal terminology will elaborate, but as an experienced and educated native English speaker I can see absolutely no difference in meaning between information "dated 31st March", "current on 31st March", "provided on 31st March" and "as of 31st March", and (with respect) under no circumstances would I ever use the phrase "is given at the date of..."