I second all what Yoni wrote. Hebrew is installed and works fine everywhere else but the subject line. I have the same settings in both computers - one works fine, the other doesn't. It also worked fine in the past and something must have happened.
Another interesting fact:
I have several accounts set up in Outlook - few IMAP and one POP3.
Messages with Hebrew in the Subject line sent to POP3 are clear and readable; question marks or gibberish in those that are sent to the IMAP account.
However, I cannot write Hebrew in the Subject line in any of the accounts that I choose, including the POP3.
Thanks.

Signature
Shai Biran
Eltiv Travel
Tel: 978-667-4849
Yoni, John,
Outlook with POP3 accounts can be run in Unicode mode when the PST file
is a Unicode-type PST file. To check, right-click Personal Folders in
Outlook, then Properties. On the General tab click Advanced. If the
Format says 'Personal Folders File', then it is Unicode format, if it
says 'Personal Folders File (97-2002)', then it is ANSI format.
> I second all what Yoni wrote. Hebrew _is_ installed and works fine
> everywhere else *but* the subject line. I have the same settings in both
[quoted text clipped - 35 lines]
> receiving mail with Hebrew in the subject line the Hebrew letters are
> replaced with question marks
yoni - 06 Mar 2008 09:39 GMT
Pat:
I get an error:
"the operation failed. An object could not be found"
> Yoni, John,
>
[quoted text clipped - 43 lines]
> > receiving mail with Hebrew in the subject line the Hebrew letters are
> > replaced with question marks
yoni - 06 Mar 2008 10:38 GMT
OK.
I can read the subjects in Hebrew now. I can type in hebrew and I can enter
Hebrew into the "To.." line.
But if the person has their name defined in Hebrew or they use a hebrew
filename for an attachment, I still get ??? ??? ??? (question marks)
What could that be?
> Yoni, John,
>
[quoted text clipped - 43 lines]
> > receiving mail with Hebrew in the subject line the Hebrew letters are
> > replaced with question marks
Pat Willener - 07 Mar 2008 02:35 GMT
That shouldn't happen; you either should see everything garbled (or
???), or everything correct.
- Is the message sent with the correct encoding?
- When you look at the message headers (View | Options), what do you see
in the From: line? Does it show an encoding prefix? Does the Subject line?
> OK.
> I can read the subjects in Hebrew now. I can type in hebrew and I can enter
[quoted text clipped - 51 lines]
>>> receiving mail with Hebrew in the subject line the Hebrew letters are
>>> replaced with question marks
yoni - 09 Mar 2008 10:52 GMT
To: "=?UTF-8?B?16nXnNeY15nXnSDXpNec15XXoQ==?="
and
Subject: =?UTF-8?B?UmU6INep15zXmNeZ150=?=
What does that mean?
> That shouldn't happen; you either should see everything garbled (or
> ???), or everything correct.
[quoted text clipped - 58 lines]
> >>> receiving mail with Hebrew in the subject line the Hebrew letters are
> >>> replaced with question marks
John - 06 Mar 2008 17:29 GMT
OK, so how do I change the type from ANSI to Unicode...?!
> Yoni, John,
>
[quoted text clipped - 41 lines]
>> receiving mail with Hebrew in the subject line the Hebrew letters are
>> replaced with question marks
yoni - 06 Mar 2008 18:59 GMT
That I got.
You need to add a new PST File to your outlook, set it as Deafult then copy
over all the items from one to the other.
It's easy.
Sorry, I don't have time to explain more, but just google "Convert Outlook
PST file"
> OK, so how do I change the type from ANSI to Unicode...?!
>
[quoted text clipped - 43 lines]
> >> receiving mail with Hebrew in the subject line the Hebrew letters are
> >> replaced with question marks
Pat Willener - 07 Mar 2008 02:32 GMT
"Copy over"... use drag-and-drop.
> That I got.
> You need to add a new PST File to your outlook, set it as Deafult then copy
[quoted text clipped - 50 lines]
>>>> receiving mail with Hebrew in the subject line the Hebrew letters are
>>>> replaced with question marks