Plugin/WordPress Updates Won't Unpack

Hello,

I’m trying to update a few of my plugins (bbpress, contact forms, etc.), however once I click “update” it makes it past:

Downloading update from http://downloads.wp.xz.cn/plugin/contact-form-plugin.3.71.zip…

but then stalls at:

Unpacking the update…

This is true for most plugin updates and for the wordpress update to 3.8.1 (eventually I updated wordpress manually, but I’d prefer not to have to manually update all plugins every time).

Thanks in advance for any help that you might be able to offer!

My site is here: http://mlsinc.ca/blog