Spell checking; Issues resolved including 'The word specified must be a single word' runtime exception

If the User Preferences, Spelling, Supplemental Entries or the Global Settings, Spelling, Supplemental Entries contained more than one word per line or, if the word contained certain invalid characters, e.g., a space or a '/', attempting to open any form that implemented spell checking resulted in the following error:

An unhandled exception has occurred. The word specified must be a single word.
Parameter name: word

Also, the Email Message wizard was not respecting Spell checking settings and would always display the Spelling dialog when moving to the next wizard page, regardless of whether the the User Preferences or Global Settings, Spelling setting to automatically check 'Email Messages and Subjects' was checked.

NOTE: The above only applied to the Email Message, not the Subject and would also apply to any other forms that allowed entry of HTML Email Message details.