Problems with word as e-mail editor

Hello,
A colleague has asked the following question, & I don't know the answer ...

OS - MS WinNT4SP5

"Not sure how you query it but basically, when the always check spelling option is ticked, while using Word as an email editor on this user'smachine, he keeps getting error The Operation Failed."

HELP!!!!

I've reinstalled outlook and word;..checked every last details, I'm tired!!..it works fine on my machine, (Fujitsu B142/NT4 & Compaq 733EN/NT4 - Both SP5)

I'd be grateful for any assistance that you can offer

Thank you

Arthur