cannot open *.msg attachments on computer

Outlook2003 SP2 on Windows XP SP2
One computer (any user on the computer) does not enable opening *.msg
attachments. Message along the lines of "unable... contact your system
administrator".
Same attachments accessed from another computer with the same configuration
open, so it is not the messages themselves.
I have tried reapplying the file type to Outlook.
There is no google desktop on that computer, only WDS.
In the past we have had a similar problem with calendar and task
attachments, and the solution was to register the mlang.dll. However, this
does not seem to apply to the *.msg format.
Can anyone tell me which dll works on the *.msg format? Or maybe suggest
another solution to the problem (other than reinstall Windows, which is
really the very last option if nothing else works)?

Thanks,
Ofra