Orbiting in 3D causes the Viewport to Switch from Orthagonal to Perspective

I (3 days ago) upgraded to Fedora 16. I also upgraded my Blender version. It’s r45201, and the link is right here http://graphicall.org/805.

After resolving dependencies and porting over my default files and addons and whatnot, I ran into a huge problem that is so irritating I can’t use Blender till it’s fixed. As stated in the title, whenever I orbit in the view-port, the it automatically switches from orthogonal to perspective. It only happens when I orbit, it does not happen when I pan either up/down or left/right and when I zoom in/out from the current position.

I looked thoroughly through the keyboard shortcuts, but I still couldn’t find anything. (I don’t know if this helps, but I’m a medium-advanced Blender user.)

Thanks in advance for any suggestions.

EDIT:
I figured it out. In case other people need it, the key is to use the default file of a slightly older version of Blender. You have to plug your addons back, but it works.