I walked into an issue regarding spell check in MOSS today.
SiteA with UserX having Read permissions because of SiteA Visitor group membership
List in SiteA, with specific permission for UserX as Contributor. You will need to break permission inheritance to accomplish this on the List.
When UserX opens up the list and creates a new listitem, the user can no longer use the Spelling feature. Each time the user clicks the Spelling… button, he gets an error message displaying: “Spelling did not complete properly. If this problem persists, notify your system administrator”.
You can also repro this issue if you define Contribute permissions to the SiteA Visitor Group on the List.
This error is apparently due to the fact that the user does not have contribute permissions at the root level of the site and is known as a bug which should be addressed in SP1 for MOSS.
I reproduced this error on my test environment that does not have SP1 installed.
– After the installation of WSS SP1, the behaviour was still the same.
– After the installation of MOSS 2007 SPA, the error no longer occured.
So if you encounter this error in your environment, consider upgrading to MOSS SP1.