I’ve seen a few posts about 2.40 breaking the famous walkthrough_template.blend from the Blender site (used as the smoothest first person camera view for walking around interactive environments).
After running a file with the walkthrough_template.blend for the first time in 2.40 it will delete the link between the viewer object and it’s attached IPO. This results in an inability to turn the camera left and right. Erwin has mentioned on the Blender dev forum that this is a result of his work on the record to ipo function.
Fixing this is easy. The IPO (Oblpo) has not been deleted it’s just been replaced by an empty IPO (viewer). Select the “viewer” object of the actor and set it’s IPO back to Oblpo (it will still be in the list). You only have to do this once and Blender will not break the link again.
Maybe somebody with the correct permissions and access could do this for the file on Blender’s site and the walkthrough_demo.blend in the game regression suite.
Hope this helps.