[Owncloud] PHP module mb multibyte can't be found after ownCloud update

[Advrk Aplmrkt]

Hello,
I've been trying to ask this question and would really appreciate some help.
I have been running ownCloud from the git repository for a few months,
testing features, etc. It runs on my Scientific Linux 6.1
(http://distrowatch.com/table.php?distribution=scientific) machine,
which is just RHEL 6.1 without the brand.
However, a couple weeks ago after a "git pull" update, I keep getting
the following error when I go to my ownCloud front page:

"PHP module mb multibypte not installed"

I did not remove any existing PHP modules on my system, so is this a
new requirement? Or is ownCloud somehow not finding the module?

In any case, can someone please help??? I don't know anything about
PHP so specific instructions would be great. Thanks.