install guide given in first post: new location, no old versions. everything rewriten for reasons. you cant mix it with old version. you will have all kind of problems if will mix 5.82 and 5.90. and of course dopus5.90 do check if dopus already running or not , but since 5.90 everything new there can be bugs because of which it didnt detect old sasc version.
in other words, new location must, and only files which come in archive. no old modules, libs, etc. first make it works as it, then you can add additional stuff to see how it will be.
as for assigns: you may not have any, or just dopus5: one will enough (to new location of course)