If you are using Autoruns to disable some Explorer dll(shell dll), it will remove the current registry value and showing it fail to find the file.
http://forum.sysinternals.com/bug_topic30729.html (http://forum.sysinternals.com/bug_topic30729.html)
Based on the PSTools, it look like somehow it will replace the space into ":", for example, "Program Files" will become "Program:Files" and fail....
For Autoruns, you can use CCleaner as a temp software to disable context menu dll, or older Autoruns if you still has it on your hard disk. :)
I use it but not the explorer tab , good to know though.
Yup, and lucky I am using it for control the software that I can get the context menu back very easy, like the Winrar. ;)
I forgot to update this post, this issues is fixed, but still remember to back up the registry before you change it, it may still got some hidden bugs. :)