You need to cancel all depreciation entries for the FAs in question created in 2011 first - Navision will not allow you to post anything before the date of last existing entry (and they are incorect, as BV actually must be different from Dec-31-2011)
How to do this - it’s a lengthy process, as you must do it for every FA one by one. (in fact, it can be done in bulk - but if you are a beginner in FA, I simply would not be able to describe the workaround method to you, sorry )
I have posted here earlier several times how to cancel FA Ledger entries, on the spot I found this one: http://dynamicsuser.net/forums/p/27055/145325.aspx#145325 but there must bo other threads, too.
Please use Search, you will obviously find more posts…