Here is a direct link to my post in the aforementioned thread word 2007 send to buttton greyed out
I think that your problem is stemming from not having the correct privileges when making the changes to your registry. Because the keys we are modifying are in the HKEY_LOCAL_MACHINE (HKLM) branch, we need to use an account that has administrative privileges.
The easiest way would be to use the batch code I provided and follow these instructions (take notice of the bits highlighted):
Originally Posted by Dwarf