I'm going to make a suggestion and I suspect you won't like it. I've recommended this to another expert level programmer and he was not thrilled at all. 

The problem with your VM is solely to do with its installation, I'll wager. How you put the VM on the machine is, I suspect, the problem. 

Did you run some kind of script to install the VM on your machine? My recommendation is to never do that. Download a VM from mirandabanda.org, run it on the command line, and leave it at that. [1]. VM install scripts have shown me twice two very skilled programmers run aground. Don't do it. 

As I said, I don't think you're going to like this suggestion. And you may think it's amateurish, but I've never had a problem. And I can think of two other expert level programmers who practically hung themselves. If Eliot says "This works on Linux" then I believe him. 

My 2 cents, 
Chris 


[1]
'/home/chris/Desktop/coglinux/lib/squeak/4.0-2761/squeak' '/home/chris/Desktop/VMMaker/Squeak4.5-13680.image' &


[2]
chris at chris-Dell-System-XPS-L322X:~/Desktop/2151/unix/build$ lsb_release -a
No LSB modules are available.
Distributor ID:	Ubuntu
Description:	Ubuntu 12.04.4 LTS
Release:	12.04
Codename:	precise

On Jun 3, 2014, at 12:16 PM, Bert Freudenberg <bert at freudenbergs.de> wrote:

> 
> On 03.06.2014, at 17:51, Chris Muller <asqueaker at gmail.com> wrote:
> 
>> On one machine only, I'm getting an error when I try to start any image:
>> 
>> --------------
>> could not find display driver vm-display-X11; either:
>> - check that /usr/local/lib/squeak/4.0-2776//vm-display-X11.so exists, or
>> - use the '-plugins <path>' option to tell me where it is, or
>> - remove DISPLAY from your environment.
>> ---------------
>> 
>> Of course, none of those suggestions worked, and I have been running
>> Squeak for a long time on this box with no problems.
>> 
>> The same image starts fine on other machines, so I'm guessing
>> something has gotten hosed up with my Ubuntu 14.04 installation on
>> this one box?
>> 
>> Any suggestions are appreciated.  Thanks!
> 
> Does "ldd" output on the X11 module look right?
> 
> - Bert -
> 
> 
>