Has anyone experienced this error? Any solution? I appreciate any help.
The problems you are experiencing are fixed in the internal build (ver. 4.1.1367) released this week.
Also you can find the solution in this post: http://www.sitefinity.com/devnet/forums/sitefinity-4-x/general-discussions/object-reference-not-set-to-an-instance-of-an-object-in-design-template.aspx
About your second issue there is a PITS logged. The ID is 5606.
As a workaround I can suggest you :