So, why don't you go the easy way and just install mupen64plus from Ubuntu
software manager? It is available from Ubuntu Universe archive [1] and from
two different PPAs [2].
> Anyway, help would be appreciated.
And for the rest, please read the console usage guide [3] (in case you use
1.99.x... 1.5 still has a GUI bundled with the official sources).
Kind regards,
Sven
[1] https://help.ubuntu.com/community/Repositories/Ubuntu
[2] http://code.google.com/p/mupen64plus/wiki/DistributionPackages
[3] http://code.google.com/p/mupen64plus/wiki/UIConsoleUsage