I can answer this question. I'm the creator of Doradus 8)
You'll have this problem always with any spacecraft.dll ship, but it has also an easy solution. The problem itself is that
you cannot reference twice the same ini file to spacecraft.dll module. It will directly CTD if you do it.
Of course, the solution is obvious: you can copy doradus.ini file with another name, as example super_doradus.ini or
whatever other you want. You must also copy and rename the doradus.cfg file to the same name than ini file and
change inside it the following:
; === Configuration file for Doradus === (recommended to change the name, but not necessary)
ClassName = doradus (here you must put the new name without any extension)
Module = spacecraft
EnableXPDR = TRUE
XPDR = 400 (if you want another radio transponder, you must change it here)
And into the scenario file, you must reference the new ship. if you called it super_doradus, then you must call it:
super_doradus:super_doradus
STATUS Orbiting Earth
RPOS 9195706.59 -766783.72 -1086318.56
RVEL 645.782 -190.030 6402.776
...
...
...
END
I hope this can help you to have a dozen Doradus class freighters crossing the solar system.
Hispa.