12.04 (precise) 64-bit Kernel Linux 3.2.0-39 3.6GB memory Intel Core 2 Duo CPU @ 2.40GHz x2 WUBI-installed Ubuntu running on a MacBook Pro 7.1 with OSX running Vista via Boot Camp (hey, I like lots of OS's m'kay?)

When installing from Ubuntu software center my system very frequently freezes. This has happened 4 of the last 5 installs. Most recently I was installing the Google Earth .deb from Google's website: clicking the .deb file automatically opens Software Center (otherwise I would have used Synaptic, as I've grown to expect Software Center to freeze my system and I'm rather tired of it.)

By "freeze" I mean nothing works: no dash, no launcher, no mouse movement, no alt-tab, can't open terminal (keyboard does not work). Software center does show the "installing" icon but after that it greys out and I can't click anything.

REISUB has no effect but a cold power-down and restart is possible.

Occasionally, after 5-10 minutes, I'll be able to move the mouse / use the keyboard and run a launcher command or two, although other open apps (Chrome and Software Center) will still be greyed-out/frozen. (I've never waited longer than that - if still unresponsive after 15 minutes I just power down and restart.)

Most recently, which is why I am finally posting a question, I waited about 15 minutes and was finally able to open System Monitor while this was going on. Processes tells me that System Monitor is using about 20% of CPU, and nothing else is using much (zeros mostly). In fact I didn't even see Software Center listed? However at this point the system finally partially unfroze, the installation completed, and while I wasn't about to close Software Center I was able to do a system shutdown and fresh restart and I went and took a look at the syslog.

In /var/log/syslog I see a lot of ":blocked for more than 120 seconds" messages. Similar to

ubuntu hang out with this message :blocked for more than 120 seconds

Which has not been answered, and I'm not running a virtual machine.

My full syslog with stack traces looks very, very similar to this:

Why do tasks on Amazon Xen instance block for over 120 seconds causing server to hang?

Note that that question was solved, but that's because the problem was being caused by Amazon and Amazon fixed the bug. I'm not running anything Amazon-related. My syslog does look very similar, however.

My question is also similar to this:

Troubleshooting server hang

But the referenced "duplicate" in that question is about how to kill processes/restart when the system freezes. I know how to kill processes and restart. I want to figure out what is causing the problem so I can try to fix it. I realize that I could just use Synaptic instead of Ubuntu Software Center, but I'd like to try to solve the problem if possible.

I'm thinking I should perhaps submit a bug report, but I wanted to first see if anyone else was having any similar problems, and if so what you all did to fix it.

I see a number of questions about Software Center freezing and others, including those I linked, about the "blocked for more than 120 seconds" log error, but I didn't see any question that links the two. I did save a copy of the syslog report if anyone wants to see it, but as mentioned it's quite similar to the one posted in the Amazon-related question...and I didn't want to take up even more space unnecessarily as, my apologies - this question has already become extremely verbose!