Office 2003: "Add to dictionary" not working.

Get to:
Tools/Options/Spelling & Grammar/Custom Dictionaries...

Select your Custom.dic, then click Modify.
If you cant modify ur Custom.dic than means it has been corrupted.

Enable view Protected operating system files (remember to disable this
when you are through)

Folder options/View/
radio button: Show hidden files and folders.
uncheck: Hide protected operating system files.

Locate and open the Custom.dic file.
The Full path shuld look like this:
C:\Documents and Settings\user\Application Data\Microsoft\Proof

On opening and scrolling through my Custom.dic file (in a notepad), I
noticed that some sections were corrupted, viz:
"INDX( Ä
4s , ( 8 è Ç
1 Æ
1 ......................"

I simply deleted the corrupted sections, and saved the Custom.dic
file.

This solved my problem.

The Add to Dictionary was restored.

NB:
If you hav multiple Custom.dic files, and any of them is corrupted,
and you have them checked alongside the default in "Tools/Options/
Spelling & Grammar/Custom Dictionaries...", the same problem will
persist.
It might be good if you can corrected all the corrupted *.dic files,
or uncheck or even Remove any *.dic file that still corrupted.

Cheers.
Tony.
http://tonyblu5.blogspot.com
http://job4vacancy.wordpress.com