Known bug when trying to edit DTS packages:
described here, but the two links in the article – Microsoft SQL Server 2008 Feature Pack page and Feature Pack for Microsoft SQL Server 2005 page.
Microsoft SQL Server 2005 Backward Compatibility Components available on both links, but only on the second one it will work with 2008R2 (Despite the fact that the date of Feature Pack release is earlier).
In addition, here, in the first comment are correct pathes to copy *. dll and *. rll files.
In SSMS 2012 DTS package management is discontinued.
