Office 2010 - "Excel cannot complete this task with available resources."

We recently upgraded to Win7, Office 2010, and new machines with 8gb RAM.
 
We've had a number of users report the following error when trying to open multiple files within Excel:

"Excel cannot complete this task with available resources. Choose less data or close other applications."

We've been able to alleviate this issue for many users by disabling the Explorer Preview Pane, but I was wondering if anyone had any other solutions as I just had another user report this was still happening even after disabling the Preview Pane. Most of the Googles tell me to reinstall Office, upgrade the RAM, or other things that don't really address this issue happening on multiple brand new, fairly beefy machines. I have noticed that a lot of the users reporting the issue are working with sheets with fairly lengthy, though very simple, CONCATENATE formulae, which I was able to replace with simple "&" combinations. Unfortunately, I don't know how many of our users are using Concatenate without issues, so I don't know whether I can just blame that.

Yes, I know this is an old post, I’m trying to clean up older posts that are unanswered.
Did you ever figure this out?

Not really. It still comes up every now and then where disabling preview pane doesn't resolve the issue, but it's not too frequent.