There is now a HotFix that addresses this issue:
Came across an odd bug when adding PerformancePoint content to a standard Web Part Page.
“The selection is not a valid PerformancePoint” whatever…
Took my a while to realize that for some reason the Location path was using the PerformancePoint item link:
The actual path should be:
Not sure why Sharepoint inserts the former URL instead of the latter. You can see what the path should be in the selection dialog box.