F-Spot won't start

[thephotoman]

Eamonn Sullivan wrote:
> On 10/15/06, thephotoman <rantman_2000 at yahoo.com> wrote:
>>>> |** ERROR **: file class.c: line 2505 (mono_class_setup_parent): should
>>>> |not be reached
>>>> |aborting...
>>>> |Aborted (core dumped)
>>> Hmm... It runs fine here and the error messages are indicating that
>>> bits and pieces of Mono are missing. Before upgrading, did you have
>>> the meta-package ubuntu-desktop installed? Try installing it now and
>>> see if that fixes the problem:
>>>
>>> sudo apt-get update && sudo apt-get install ubuntu-desktop
>>>
>>> -Eamonn
>>>
>> Apt tells me that ubuntu-desktop is installed and is the latest version.
>>   The failure and output do not change.  Furthermore, there are no
>> annoying third party repositories screwing things up, as far as I can
>> tell.  Even re-installing or compiling F-spot does no good.
> 
> Hi, going back over the messages in this thread, I see that you're
> loading f-spot from /usr/local, not the one that came with
> ubuntu-desktop. Did you, by any chance, install f-spot by yourself,
> from sources or something, under dapper? Check your MONO_PATH
> environmental variable and make sure it isn't trying to load an older,
> local copy of Mono or F-spot. F-spot is now official in Edgy, in main,
> and part of ubuntu-desktop.
> 
> -Eamonn
> 

Loading it specifically from /usr/bin results in the same error message. 
  Where is the MONO_PATH environment variable, so that I can check that?