edit(Fixed) Database Error for some people in some or all topics

[cmonkey]

For some reason, some people in my 1.1 RC2 forums are no longer able to post replies in certain topics or new topics, and a few are unable to post at all.  Upon posting, they receive a generic database error:

Database Error
Please try again. If you come back to this error screen, report the error to an administrator.

The error does not appear to be related to any OS, browser, skin, user group, or anything else at all.  It seems to occur to a lot to some people and not at all to everyone else.

The forum error log lists many occurances of two errors.

The first is:

Database Error: Duplicate entry '[' for key 7
File: /*********/forums/Sources/Subs-Post.php
Line: 1505

Line 1505 appears to be:
SUBSTRING('$posterOptions[ip]', 1, 255), " . ($msgOptions['smileys_enabled'] ? '1' : '0') . ", '', SUBSTRING('$msgOptions[icon]', 1, 16))", __FILE__, __LINE__);

The second is:

8: Use of undefined constant pm_short - assumed 'pm_short'
File: /************/forums/Themes/default/BoardIndex.template.php (main_above sub template - eval?)
Line: 494

I have searched around and have found no solution.  Does anyone know what the problem could be?

[cmonkey]

Fixed?
I appeared to have fixed it by changing $msgOptions['smileys_enabled'] to '$msgOptions[smileys_enabled]'