The above is rather interesting. Often argument counts are determined by a space character. I know that in the past there were issues with either (A) spaces in file paths (such as the home directory), or with (B) non-English character sets introducing white space, or (C) just a space somewhere normally unexpected. It is a big leap in imagination, but it is possible that if the user can create a host PC account without spaces and using the “en_US.UTF-8” character set, it could just “start working”. It might be a lot of work for no reason, but if this is the reason, then it will save a lot of time.
Unfortunately, the easiest way to do this is to change the default locale of the computer as a whole, and since this might mess up something in the original account I am not going to recommend doing that. Would your user happen to have a second computer which could be set up with en_US.UTF-8 locale?