Statistics on filestream column
If you have applied the latest update for SQL Server 2012 - Cumulative Update 2 for Service Pack 3 as at the time of writing - and the issue persists, you should open a support ticket, or report the issue on Connect.

The underlying issue shares some common features with an existing report:


String summary - slow statistics creation on VARBINARY(MAX) column


...which might give you some ideas for a workaround.

For example, there is a small chance that creating statistics on a computed column casting the column to varbinary(200) might work. That cast may also explain why the auto-stats succeeds while you cannot create statistics manually.