You are running a very old patch. There have been issues with this functionality for as long as I remember.
Maybe review the following fixes in the following post to see if it is fixed in a later version.
“Change Data Source” or “Change Data Source OLAP” should find the relevant ADAPTS, if they exist.
https://bobj-board.org/t/212450
Mak 1 
(BOB member since 2005-01-06)